Quarter Glass Power Window Will Not Raise On Convertible

My rear driver-side quarter window had been making a grinding noise, sort of like a twig breaking apart, for months. I figured that a twig somehow made its way behind the rubber body seal near that window and ignored it. Well, two days ago I put the top down on the vehicle, along with the windows, and they all came back up except for the one that was making the noise. When I try to engage the power window option, all I get is that grinding noise but no movement whatsoever.

I'd like to avoid a repair at this time, if possible. Is there a way that I can manually lift the window to seal it? I tried pulling the window up already, but it seems to be secured in the down position. If this is better left to a mechanic, what should I expect in terms of cost for the repair?