You can buy a patch panel and replace just that area, or you can replace the whole pan, depending on what the other side looks like. If you go with patch, leave the windshield wiper holes alone and cut the patch to miss these holes. Ask me how I know!
The other side looks absolutely no better, I can't finish the engine compartment until I get this finished. Damn just when I thought things were looking up. I stumbled across a very soft spot and happened upon this madness and I think I am going to replace the whole thing just to be safe. That is going to put me back about 2 weeks