The glass on mine was scratched, so I took it off (easy) and took it down to a glass shop. They made me a replacement while I waited, and I think it cost all of twenty bucks.
Regarding the rubber.. there is a product called liquid electrical tape that comes in a can with a brush on the lid. I think I got mine at a big box home improvement store. It is made to stick to rubber/plastic/etc and would most likely work very well in this instance. If you can find a spot to test it first, that would be the most prudent.