To remove the rear door panel, do the following:
1. Remove the pocket where your hand goes to shut the door. There is a screw holding it in place. It will simply lift out once the screw is undone.
2. Undo the screw holding the door handle in. Then pull the handle out slightly so that it's not sitting flush with the panel.
3. Pop up the power window switch panel with a flat head screwdriver. It's best to pop it from the front. It will lift up and allow you to disconnect the wiring harness.
4. There are two push-type clips on the side of the door panel. In order to get these out you must push the center in. Use a small screwdriver or a ball point pen to push the center in and then flick the main clip housing out with a small flat head screwdriver.
5. Once all of the screws/clips are removed, pull on the bottom of the door panel and you will hear the clips pop out.
6. The door trim will now be completely loose, so all you need to do is lift it up and take it off. Getting the door handle through the trim is the hardest part, but if you turn the handle on an angle it will go through very easily. Alternatively, just disconnect the metal arm from the door handle.
It's not as hard as it sounds and should only take you 10-minutes or so if it's your first time doing it. Personally, I think it sounds like it's time for a new electric window regulator. You may get lucky and find that it has come off track, but in most cases it's the regulator at fault. In the meantime, hold the window up with small chocks of wood.
Good luck