Help replacing window glass

My driver window has been acting screwy lately ie: stopping halfway up or down and coming off the track...

Anyway, I took the door apart and found that the rear most roller has eaten itself so small that it won't stay in the track any longer. And it doesn't look like the roller is replaceable. So I have another window in my parts car but I'm stumped as to how it comes out. I've unbolted the entire regulator mechanism, but the ends have rivets that look to be getting in the way for the plastic sliders to come out.

I hope I don't have to drill any rivets out. If there's anther way please let me know!

Well, turns out I saved myself a bunch of work! What happened was the little plastic roller had come apart from the little ball that it snaps onto. It was still lodged at the top of the track so it was hard to see. I reached up there and pulled it back down. It snapped right back on and all was good!