Pella

It looks like someone installed a casement window sideways, so as to act as an awning window. Your operator isn't a design that's made anymore but our 39-386 and 39-385 are similar in design. I cannot guarantee these will work, but I think they're worth considering at least. Look them over and see what you think.

I should also reiterate that these are meant to install on casement windows, meaning they're meant to install on the sill, not the sides. Just something to keep in mind.

Alternate image for 39-386