Replacement for OPO52020 casement hardware

I am looking to replace the chipped "housing" and crank handle for my casement windows. The windows open and close ok. But the housing is beaten up and the teeth that hold the handle are shot so the handle sometimes slips when trying to open the casement. I am not sure how much I need to replace or if I can just get all the parts on the inside of the window. I would love to get the type of handle that lays down when not in use. The housing appears to be about 4.5" long and about 1/2"-3/4" high. It is white metal mounted in my vinyl replacement window. On the arm of the casement hardware is the name Roto and the part no. OPO52020. Hopefully that helps determine if you have a product that I can use. Thank you for your help.