Did ran into this issue some time ago with a corrupt backup...
There are some Windows and Mac Apps out there that read the backup and then you can extract the data from there and ssh them back to your iOS device.
Its a pain in the behind, but the only way to get the info back if iTunes does not work for you.
I used MobileSyncBrowser with great success (cannot link to it, my posting count is too low, but you can google it). It does cost US$10/$20 depending on what you want to restore. But you can download it for free (limiting on what you can restore in the free trial).
I'm now a little smarter and backup all my stuff in iTunes AND in PkgBackup!