cat door (CUF)

I am in need of a cat door for my window like the one pictured up above. This is kind of an out there request but figured I would try. I would like one with the piece that fits the standard window, but I am willing to take one pictured up above. Hope someone can help me out. I can't keep my cats inside, I have tried, so having a cat door would really give me piece of mind that they can get in an out on their own and won't be stuck outside waiting for us.