You can get a replacement door from a junk yard, online, or you can try to fix it.
If it's just the window, you can pop open the door, your gears may have gone out, or the window could've slipped off track. It can be an easy fix, or unfixable...
If you do pop the door open and find that you can fix the window there, be sure to grease/lube your gears, they will make for quicker window response times... some W-40 or mechanic's grease should do the trick.
-Scynthyace-
~1994 Pontiac Sunbird Convertible LE V6 3.1L Owner~