Being steady of hand that you are... Consider taking it apart and cleaning it up. You might be able to rebuild it. Also if you go to a self service yard you might be able to find the same motor on other vehicles... The casing might be different but have the same stator etc. I would first try to clean up what you have as it may only need cleaning. It would seem odd that a wiper motor would get wornout from use unless it rains non stop there