the winder for the window is held on by a circlip but you can usually get them off with a sharp flat head screwdriver, then just push it back on with a screwdriver to replace, after all the screws are out there are little plastic clips all around the back of the panel that hold it onto the door, just move your hands around the edge pulling it as you go,
make sure you have removed all the screws you can find they are often hiding, i think there are two large ones holding the handle on, one on the door opener handle (pull the handle out and you'll see it) should be a couple along the bottom of the door and a few holding the interior part of the wing mirror.
you may be able to get inside without taking the winder off by unscrewing all the screws and pulling out all the popper clips and then just twist the door trim clockwise or anti clockwise, my wifes was electric windows so im not for sure.
my wifes was an older model but nearly all cars are similar in the way you remove the door lining just screw winder and plastic poppers, if you have one of those storage pockets at the bottom of the lining there are screws with little caps covering the heads, use a small screwdriver to remove the caps.
she hasnt had the grand prix for a couple years now and my memory isnt that great sorry
