Linebaugh:
First of all you will need to know the OEM manufacturer and model of your shower glass enclosure. If there isn't a tag on the enclosure somewhere that you can see, you need to call Heartland Service with your VIN in hand for them to look at your build sheet, and get you this information. Heartland Service might make some sort of repair suggestion, but I would research the internet and call the enclosure manufacturer for guidance. Who knows, they might give you the part for free. If the door is screwed to the enclosure frame, it would seem to be made to be serviceable. If it is riveted to the frame, you have some decisions to make. You might even call a local independent RV repairer for advice on the matter.
Good luck!!!
On edit: You might also contact a local glass repair shop, to get their advice on the job, and maybe a bid.