How can this be repaired?

you could get a replacement from somewhere like pull apart for like $3 and look on youtube i bet someone has a video on how to take it apart and replace it or you could get a haynes manual on your car

Buy a used one off Ebay, or get one from a junk yard. Some handles are press fit on to a spline, others have a set screw in the bottom that secures it to a flat on the shaft. Either is easy to remove, particularly if you don't have to wory about damaging the one that is on there ... it'* already broke. If you can't figure it out, post good pics on the forum and we will help you with it.