Rust repair advice, wanted
 

Was going to sort out the broken linkage for the boot/fuel lid opener and while doing that noticed a rust spot next to one of the bolts securing the drivers seat.

Went at it with a Dremel grinder and the hole just grew bigger and bigger. Think I have got rid of the rust because the surrounding metal seems solid. Should it be filled with some solder or even welding or what should I do?

http://img.photobucket.com/albums/07...nFord/rust.jpg