Can I recover a backup file (and notes)?

I have a 2G iPod touch. Here's the nutshell:

*Upgraded to 3.0.
*Jailbroke on 3.0.
*Put apps into folders.
*Accidentally upgraded to 3.1.2.
*Jailbreak and folders were erased, but apps (incl. Settings) remained hidden.
*Finally had to downgrade back to 3.0, which unhid all the apps, but erased all my data.
*During downgrade, iTunes backed up my iPod, which erased my previous backup file (which still had all my data even though it was hidden).

I had plenty of data that I don't want to lose, but my Notes were by far the most important. I've looked and looked, but can't find any suggestions on how to recover them, considering that iTunes got rid of my backup file. When it does that, does it just throw it in the trash somewhere, or actually overwrite it and completely get rid of it?

I *REALLY* need to get those Notes back, and would appreciate any help offered. I'm on Windows XP, and don't appear to have the \Application Data\Apple Computer\MobileSync\Backup\ string anywhere on my computer.

EDIT: I also have an executable called AppleMobileSync and a folder called AppleMobileSync.app . The folder contains \Contents\Resources\iPodSyncClientImages.icns but I don't know what any of that is.

 

Bump, in hopes of rescuing some information of great personal importance.

 

I was syncing it with iTunes. The notes showed up there in my library, but that disappeared after I restored back to 3.0. I do sync my iPod calendar with my Outlook, so I checked that, but the notes aren't there.