My ipod touch 8 GB won't sync.

I have the ipod touch 8 GB. It was previously synced to my old computer that I no longer have access to since it had hardware failure. I want to try to re-sync my ipod with my new itunes library I have; however, when it says it's going to delete what's currently on the iPod and replace it with what I want to sync it's saying I won't have enough space to sync everything, when clearly at the bottom of the size bar it said with everything I picked I would still have 2.0 GB of memory still. Someone please help. I don't want to restore the iPod completely, but I might have to in order to get it to sync correctly.