Here is another source in the Greater Toronto area. I have dealt with him once and am a satisfied customer.
Automotive Detailing Products - GTA
You may need to use a random orbital polisher with a polishing compound (on a orange pad) such as Mezernas to get it back up to a "clear" view. On headlights use 2000 grit wet sandpaper to get rid of the crud buildup. The use a polishing compound with above polisher. Using the same may work on the plexiglass window. I use Plexus on both the rear window as well as this wind screen.