If you can, you might be able to replace just the handle itself without removing the assembly. If you remove the metal rod to the door release, I believe there is a pin that holds the spring in place. If you can remove that pin, then I think you can just replace the handle, and reassemble.
If you can't do it that way, then you can drill out the plastic weld spots, and then use some small sheet metal screws & washers to secure the new assembly.
Like my earlier post, I'd recommend gluing in some kind of reinforcent to keep from having to do it again...
Found my old one (can't believe I saved it) so I posted a couple pics...
In this pic, you can see the pin you need to remove. If you can get that out, you should be able to work the old handle out, and the new one in. A minor PITA to compress the spring to get the pin back in.
If you have to replace the whole assembly, you can see the four weld points that I drilled out. Be careful not to drill out too far...you need something for the screws to bite into.
This one shows the failure point. I tried to fix the old one with a washer, but it was too far gone. But I did use a similar washer on the new handle to give it a little reinforcement.