That's gonna be a sod to repair.. That bit rarely breaks, it's always the 'finger/plunger' that snaps.
The main problem is that it has a pressed in pin that's bigger than the other, smaller pins that secure
the finger bit that opens the lock, which means that it's a sod to drill out and then secure it back in.
I've done one or two but after a bit, the pin always backs out again leaving you as you were before..
I've got a few spare if you want to try and repair the handle, let me know and i'll pop one in the post.
Almost forgot a very important bit, always grease the components throughly and make sure that the components move freely
without any tight spots, some of those repair kits available on the net are utter crap.
Also make sure that the door itself doesn't shut too tightly as this will also strain the mechanism alot, loosen the striker if ness.