Just went through this. Take the one out of the opposite side and take it to a glass shop. They can either cut you a piece of laminated glass right there (same as windshield glass), or use yours as a pattern and order you a tempered glass and 2-3 weeks to come in. If they can't go to another glass shop that knows what they are doing. The laminated will be a bit thicker but will fit with a little massaging and some soap on the rubber to help it.

If its the curved glass piece that may be a bit more difficult. I know there are companies that do it but you may have to call around a little bit more to local glass shops to find one that has a source.