need window screen

Assuming these are standard window screens you can go to any big box hardware store (Lowes ect) and buy a kit to make the window screen. Not hard to do if you are minimally handy. If you don't want to make one you should just ask them where you can get one made. They'll probably know, you'll need the exact measurements from the window.

How to make one

Frame Kit

And you'll need a roll of fiberglass screen to finish the job