sliding window rollers with a "T" at one end

I am in the process of making sure my windows fit and close properly. It was difficult to take out the sliding window as the top and bottom seemed to have bowed outward. I did manage to get the window out but i broke a roller. The window is made by Atrium. THE pictures show the roller mechanism. There is one place for a screw and there are wing tabs to hold the inside down. I sent pics with measurements. The windows were new in 2004.
I hope you have replacements.