Q: Ipod not syncing

hi every time I try to plug my ipod touch 4g into the computre to sync, it picks up the ipod but when I click the sync button itunes freezes while trying to sync it.

Recently when I pluged it in to try again, it came with an auto install of the new update, but once again it freezes and so does my ipod before it even started to install.

then my ipod tunred off and when it turned on again it came up saying that I have to plug it into itunes to restore it. But because it hasn't been syncing and I couldn't back it up I'll lose everything.

Is there anyway I can fix this so nothing will get deleted? Or will itunes do a backup before the restore?

please help me I'm kinda desperate