I would try find a parts van with a power window motor.  If you decide to
unpower it, I'll sell you the door handle and the internal window crank gears
for $15 +Shipping.  All you would need to do is take out your electric motor
and put in the manual set up (it should bolt right up.  Then poke a hole in
your door panel for the place where the winder crank attaches.  Let me know
what you think.
Ken Wilford  John 3:16