IPod Help! syncing an iPod with a new computer.?

So I have an iPod touch second generation. I bought it in June of 2009. I had it paired with my iBook G4, but then in August of 2009, the iBook finally bit the dust. I just replaced it with a beautiful new MacBook Pro that arrived today. I'm a pretty proficient Apple Macintosh user, but I'm having trouble because my new computer won't transfer any music files that I didn't purchase through the iTunes Store. I set it to manual override and now I'm worried because the songs won't drag and drop anywhere except into a playlist on the iPod. HELP MEEEE!!!!!!