Rollyson window plastic strip

We have a 20 year old Ryan (NVR) home with aluminum Rollyson windows with internal muttons.. We are hoping to find a way to fix this window to prevent replacing the whole house since a match would be unlikely.

Our most frequently opened window in our family room has just lost a part that began to slip out and get caught when closing the window. It is a long narrow, white plastic or PVC strip that fits along the side of the lower half of the window. It's function seems to be to hold the window tightly in and I assume would also prevent moisture leakage.

The piece is nearly flat but folded over in a U shape with one side being aprox.1/4 inch and the other side aprox 3/8 inch wide.

Any help would be appreciated!

Thank you!

Bev

I have attached a picture of the window, a close up of the broken piece, a full shot of the broken piece being held next to the window (minus the 4 or 5 inches that broke off)and a close up (excuse the dust!) of the left side of the window that still is intact. Please let me know if you have any other questions. I appreciate your help!
Bev

First I have to compliment all of you on your customer service and patience with a novice like me. You have gone above and beyond.

The 55-035 gray part's shape is closer than the 55-034 since the original does not have the ribbing similar to the 55-035. From your experience do you think the difference in shape would be an issue? Gray would look terrible. What is your opinion? I also would not know where to turn to find a handyman who would know how to replace it. Is this a common fix? Thanks for your patience with me!