Restoring iPhone from a backup

I recently moved from a PC to a Snow Leopard based Mac. I had made a backup of my iPhone 3G on my Windows based machine, and moved the backup to the appropriate location on os x (library/application support/mobilesync/backup). I've been trying to restore my iphone to the backup because my nephew screwed up my phone when he was playing with it, but iTunes doesn't show that I made a backup even though it's in the appropriate place. I tried making a backup in os x of the iphone even though it's screwed up and it put it in the same place i put the backup from Windows.

Any help would be great. I really want to restore from my backup i made in Windows without having to go find a buddy and using his pc.