The original windows are made by SE-GI, but I don't suggest them for a replacement.
You can get replacement windows made for you at this company in Florida:
SUNCOAST DESIGNERS, INC.
15050 LABOR PLACE
HUDSON, FL. 34667
This is the same company that repairs fogging windows. If a window is broken, or they break one in the repair process, they will make a new window to fit. You can ship your broken window and frame to them for repair. Their web site has shipping instructions.
When I was in Hudson, FL in January and I had this company repair 6 of my fogging windows, they did a very good job.