Yeah, probably best left for a smith to fit you with a new ejector and might as well while he's at it, a new ejector spring.
It's the sort repair where you'll need the receiver refinished afterwards. The ejector rivets get replaced and the left side of the receiver where they fit through gets worked over a little bit.
However ... There's a tool, Clark Ejector Rivet Cutter, in a drill press, that allows you to remove enough of the rivet's peened area only, without disturbing the rest of the rivet. This supposedly allows you to repeen the rivet. I've never used one, and often thought to invest the $25. to see if it works. I think that's about the only way to do this as a DIY and without a refinish.