Sunroof Removal on '91 100

[Geoff Doctor]

Ok, I just picked up a 91 Audi 100 for $250. Its a nice car, but I have 
a problem with the sunroof. The plastic parts that are screwed onto the 
actual retractable roof are snapped right near the rear side of it. 
This makes it impossible to retract into the roof, and hard to get it 
to stay closed instead of tilting. How can I remove the sunroof to 
replace there plastic things. Also where is a good stop to find them, 
the local junk yard has an Audi 90 that has similar looking parts. Does 
anyone know if they fit?

Thanks for all of your help in advance,
Geoff