update ate my songs

I hooked up to a different computer with a better iTunes version on it, and it asked me if I wanted to update my iPod. I forget what the update was called, it had something to do with Nike, but it said it would fix the bugs also, so I clicked yes. It killed everything on my iPod, and I need to know, is there a way to get the songs back? They aren't on my computer either. Also, iTunes says my iPod is now over halfway full of some unidentified junk, that I want to get rid of. I really don't wanna put all my songs in again, please help me!