There are no after market replacement windows for them. You will have to contact Dragon Care, Dragon's Customer Support service for replacements. They are usually pretty responsive.
Dragon Care:
http://www.dragoncare.com/chsmain.asp
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
Check out my Gallery: https://app.photobucket.com/u/HeavyArty
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell