94 Century window problem

My daughters 94 Century has a problem with the driver side front window coming out of the track when you roll it down.
I finally figured out the cause. There is a little plastic sort of triangular piece that is supposed to be at the top rear of the window that keeps it in the rear track.
I found this piece which was broken laying in the floorboard of her car after seeing a little round factory made hole in the window where this piece goes.
So, my question is does anyone know if a person can buy this little piece and where:confused: or do I have to come up with a whole different window that has this piece on it. Seems like a waste of a perfectly good window glass if thats the case.
Thanks for any info you have!

Try one of the chain auto parts stores that carries the Motormite "Help!" line. I believe they carry that piece you are needing and it just snaps in place. If they don't offer it for this car, the GM# is 10142872 and retails for less than $10.

Rich,
Thanks for your info. I stopped by an auto glass place and they gave me the plastic piece free of charge. I took it home, snapped it in the window, snapped the window back in the track and all is well now. One of the easiest and cheapest fixes I've done in a long time.
Thanks!