Thanks for the input.
I spent several hours this afternoon getting quotes from various body shops. The cheapest I found was $75 to weld in a washer over the hole. The cheapest proper fix was 100 for labor, plus the price of the part. That's if I take the trim and carpet out myself. The price includes some rust preventive paint, but not color matching. If I do the color matching, it's an additional $100. I think this is the route I'm going to go, just without the matching paint. Should be about $150 or so total. The shop that quoted this price to me seemed to be the most knowledgeable, and they had excellent ratings on yelp and google.
The highest quote was $352, which included everything...removal of carpet and trim, new part welded in, and color matched paint. Another shop didn't want anything to do with it.
Anyway, I'll try to get this fixed some time next week.