We replaced the same window in our 2001 Adventurer. If you're handy you can replace it yourself. You can order a new window from Atwood.
RV Components, Gas Appliances, Marine Products, Chassis Components, Seating Systems, Windows and Doors from Atwood Mobile
They have both the single and dual pane glass. The dual pane one we ordered cost less than $150.00 delivered to the door. If you decide to go this route call early in the day to make an order. If the woman who handles customer orders is still on the same schedule she works from 5:30 AM to 2:30PM. She is very knowledgeable and helpful.
Here's a link to the tutorial we used when we replaced our window.
http://www.rampknot.net/window_repai...ndowRepair.pdf
The guy does an excellent job of walking through the process step by step.
Just a word of caution. If you decide to do it yourself pick a warm sunny day. We did ours in 50* weather and it was difficult to remove the butyl tape. I had to warm it with a hair dryer to get it to release.
We purchased a 2013 Adventurer last year. They no longer put the dual pane glass in the cab side windows.