Recovering data after iPhone passcode erase

Okay, here's the situation: my iPhone 4S had a cracked screen. I replaced that screen with one that worked until I was on vacation last week; I gave in and just bought a new iPhone 5. When I connected it to my computer to "restore" it from a backup of the 4S, the only one available was from a year ago (after that I started backing up to iCloud, but I was never given the choice to restore from those backups...). When I connected the 4S to my computer in an attempt to make a new backup of it, it connected and synced normally, but wouldn't allow me to make a backup to the computer without entering my passcode into the phone... which I was unable to do, because the screen was blank.

Fine, I figured that I'd wait to get home, put the old cracked-but-working screen back on the 4S, back it up to my computer, then set up the 5 off that backup. In the meantime I used the year-old backup on the 5 and connected it to iCloud. Totally functional for vacation, but missing things like app info, texts and pictures from the past year, etc.

Here's my big mistake: my brother was sure that he could successfully enter my passcode even without being able to see the screen... so I let him try. I warned him not to try more than 9 times, and he swears he didn't, but... I just finished swapping the screens, and when I turn on the 4S I get a welcome screen and the "slide to configure" option. Either I missed some connection when putting the phone back together (I'm sure I didn't, I double-checked), or my brother failed to enter the passcode so many times that my phone erased itself.

So! Does anyone have any ideas about how to get the past year of my phone-life back? The data should still be on the 4S... nothing's been written over. Getting to it is the problem (and I'm not about to pay $100 for that software that may or may not work). The stuff my 5 downloaded from iCloud is all well and good, but it's definitely not as good as restoring from an actual backup would be.

Any and all ideas would be greatly appreciated; I've spent so much time on this by now that I am completely unwilling to admit defeat. Thanks!