Closer/seal arm bracket?

Hello, I have a left-swing casement window that is not closing nor sealing properly, I think because the bracket that slides in the track on the bottom of the window, on the hinged-side of the window, is broken and therefore does not fit in the track properly anymore. I have attached pictures both of the broken bracket at the bottom of the window, and the what I think is a matching, intact version of the same system at the top of the window. I am trying to find a replacement for the bracket, or if I can't buy just that part, the whole arm assembly. Thank you for your help!