Yes, those are SHSH blobs that @saurik captured for you and are safely stored on Cydia's server.

1) Download TinyUmbrella.
2) In the advanced tab, set "Request SHSH from Cydia"
3) Select your device and click the Save SHSH button

TinyUmbrella will request the blobs through Cydia instead of Apple's servers. Since Cydia reports that you have both 5.1.1 and 5.1.1r1, you'll have those blobs downloaded to your computer. Those blobs can then be stitched to make a pre-signed IPSW.

Note, place the iPhone into pwned DFU mode to load the firmware.

Google for TinyUmbrella.

It's the first link that pops up.

I've used both redsn0w and Absinthe on four different A5 devices. My iPad 2 CDMA had the most difficulty as it timed out when applying the jailbreak. However, a retry option was provided (Absinthe) and the second time it "took." Once jailbroken, avoid dangerous repositories and your jailbroken iOS 5.1.1 should last a very long time.

When you first started Cydia, it asked you if you wanted to keep things simple and allow Cydia to manage your blobs. Since you said you've jailbroken iOS 4, I'm going to assume you (like 99% of folks) answered 'Yes' to the question. Download TinyUmbrella, check the box in the settings portion that says "request from Cydia" - download all of the blobs @saurik has been collecting on your behalf.

It's worth a shot. iOS 5.1.1 SHSH blobs should be lurking in there.

You'll do fine holding out for an iOS 6-based jailbreak solution. With the "advent" of the Dream Team, the highest levels of cooperation have been discovered for the iOS 5-based jailbreak solutions. I have no doubt in my mind that their talents will prove highly beneficial to all of us, again.

Per the blog post:

"iPad2 owners who have both 4.x blobs and 5.x blobs will always be able to downgrade to those versions, even once you come up to 6.0 and the 5.1.1 window closes (don’t do that yet though!). You need both 4.x and 5.x blobs to qualify for the 5.x downgrade even though you only wish to downgrade to 5.x (you need only your 4.x blobs to downgrade to 4.x)"

Based on that information, you can downgrade to iOS 5.0.1 or iOS 5.1. redsn0w does not have this support as of yet. You will have to wait until a new update is released that allows this functionality.

**NOTE** If you have jailbroken your iPad 2 (especially months ago), there's a very good chance that Cydia already has your blobs. If you selected the "keep it simple" option when you first jailbroke your device, you authorized Cydia to periodically fetch your blobs for you for safe keeping. Use TinyUmbrella, check the box where it says fetch from Cydia and then pull your blobs. If iOS 5.1.1 appears, you're in luck. iOS 5.1.1 is where you want to be at.

Try a different computer. Most redsn0w issues that I've seen are computer-specific.

T-Mobile is working diligently to modify their towers to support iPhone users on their network. Many of the exclusive licensing agreements were loosened with the AT&T and T-Mobile merger debacle. For example, Birmingham, AL has quite a few pockets of full HSPDA support for iPhone users. However, in Huntsville and Mobile, iPhone users are still limited to EDGE network.

T-Mobile has been in hot pursuit of iPhone support since its inception. I have no doubt that the modifications will continue to progress so that they can coax iPhone users to their network.

I wanted to add a tidbit to caution for Verizon users (possibly Sprint, as well - could potentially affect iPad CDMA owners). Although the first adopters of the iPhone 4 CDMA have our iOS 4.2.x blobs, we are unable to downgrade to any of the iOS 4 releases because of the baseband update that was included with iOS 5.0. The MEID location was altered as a part of the baseband update. As cited in the blog post, the A5+ downgrade/re-restore method requires that the baseband be updated to the latest, even when using an older IPSW to restore with.

That being said, a baseband update including with the iOS 6 series could render your device unable to talk with the cell network towers (you will see an error dialog stating that the 'MEID is unknown'). This, of course, is not permanent - upgrading to the currently available iOS 6 firmware would fix it. So, for those iPad 2 owners with their iOS 4.x blobs that want to play around with iOS 6, be aware that until a jailbreak solution is available, a subsequent baseband update (in iOS 6) may force you into iOS 6.

My situation is simple, however. My iPad 2 CDMA works extremely well on iOS 5.1.1. Although some apps were added to iOS 6, there is very little to the new release that would make me want to update to iOS 6. Had Apple included Siri support for iPad 2 owners, the conversation would be different. The lack of a bootloader exploit further reinforces my decision to stick with iOS 5.1.1 for the time being because I can always re-obtain the jailbreak, even as the iOS 6 series progresses.

Just because an update is available, examine the risk and rewards before making that decision. As @MuscleNerd stated, for those of us who have iOS 5.x blobs only, our option is only to re-restore, and that's IF and ONLY IF we did not upgrade to iOS 6. What is more important? Built-in features in iOS 6 that can be obtained via the numerous tweaks in Cydia for iOS 5.1.1? Or, the ability to recover your ability to jailbreak in the event that you need to restore on A5+ devices?

Food for thought.

Plenty of tutorials on cooking up a custom IPSW *based* on the stock IPSW - Google is your friend. PwnageTool or redsn0w is what you want. Make sure you grab TinyUmbrella and re-download your SHSH blobs for iOS 5.1.1 (since you're already jailbroken, Cydia has your blobs for safe-keeping; however, managing your own SHSH blobs is a practice you SHOULD be acclimated and accustomed to already).

*DO NOT INSTALL STOCK IPSW* If you are not placing your iPhone into Pwned DFU mode (via PwnageTool or redsn0w) to install your custom IPSW, you're not going to get far.