94 Gp Drivers Window

The Driver side window works but it dont stay in the track. The glass just falls foward. If you hold the window up while pressing the buton it goes up and down ok. I took the door liner off and seen that there is a track (towards the hinge side of the door )that looks like the window rides in. Its bolted on to the door with two screws. I can't get the glass back in the track. It looks like there was a plastic piece that attaches to the glass that rides in this track is missing.