The rounded glass of the VW-Verkauf is a lego part. 
Fixed using white 1x1-technic bricks with one hole (from
Space Shuttle).

The big glass is acrylglass (PMMA=Polymethylmethacrylate),
also known as Plexiglas. To be found at any place, where
glass is sold.

Fixed by cutting exactly (0.05mm) using an
ordinary paper cutter and lego-bricks as ruler.
It' s easy: Scratch a few times. Break with a
piece of clothe over an table edge.
Sandpaper edges on a flat surface.
Don't try to saw PMMA by machine. The material
will melt and refreeze. Cutting in the way described
above is easy and very exact!

You can bend this material at appr. 150 degrees
Celsius... but this is rather difficult!