I think you kinda answered your own question there,
It sounds like your power motor is on its way out, from what I heard, the Grand Prix's have a few issues with short window motor life, Mine go up and down pretty slow and with effort, i'd assume they will be stopping half way in the middle in a few months,
Ive never replaced the window motors in a Grand Prix before, but have in other vehicles. If you are slightly mechanically inclined, you might save yourself on some labour costs at the shop, but if your afraid of a wrench, it might be a few hundred to get that fixed.
they really are not hard to do, Im sure you can grab a chiltons manual with a walk through step by step, or you can just start taking things apart and hope you dont have extra screws when it goes together
As for buying the motor, for things like this, it IS NOT worth tryin to save a few bucks and picking up a used one at a scrap yard, you'll just be back soon after, best bet is a dealership (for quality, NOT cost)
