If you are just looking for the glass, you can try at Vintage. I bought mine from them for my old Speedster. When I ordered my new glass a few years ago I also ordered a new rubber for the top and the bottom. They ship the glass in a GREAT wodden box that requires a deposit. I decided to keep mine since the cost to ship it back was too high.
http://www.vintagespeedsters.com/accessories/
Glass- $325
Bottom Frame- $50.00
Top rubber- $25.00
Bottom Rubber- $50.00
Buenas Noches...