broken bracket on 1983 right casement window

The straight piece in the picture with the ruler snapped off the piece on the underside of the window frame while opening the window. This is the right side open window (as opposed to the left). The first picture is of the left side window from the top that shows how the set up is supposed to be.
#1 pic: working assembly on the opposite window (left)
#2 pic: stationary bracket under the window frame which used to be attached to moveable arm
#3 pic: piece that snapped off (short diagonal metal piece as seen in pic #1.)