IPhone :: Updated To 3GS To IOS 5.1 - Stuff Missing?

I updated my husband's iPhone 3GS to iOS 5.1 just now, and a huge chunk of his photos are missing. I believe the last time this phone was synced with any library, it was his library on his old computer. So, of our two computers, neither would have been a good choice for updating, since neither could be considered the original one it was synced with. My question is this: when iTunes updates software, it backs up and restores first, so why were all of his photos not backed up and restored during this process? He had about 500-600 photos and now he only has 241. Also his playlists are gone, music was gone, a bunch of stuff is now gone. I had to put some of it back manually. Needless to say I am in a bunch of trouble for this - I have been bugging him for months to update his phone so we could iMessage each other.

Info:
PC, Windows XP