Problem with Music

I finished my animation on Sunday afternoon, before work. There's something up with the music, it wouldn't sync the way it's supposed to, as in, let's say, I have a scene that 158 frames long, when I cut the music to be 158 frames, it would be too short, so I figured out a way to make it run through the whole thing then fade out a little bit before the whole thing ends. I wanted to be able to edit the music better, but I don't know how to. Oh well. It's due tonight, and I think I did a pretty good job.