Floorpan Rust

My '63 Dart has incredibly bad floorpan rust. There are several holes. Until I can get around to getting someone to weld new metal in, what is my best bet to stop the current rust from spreading?

http://i16.photobucket.com/albums/b35/RpgMakerXP/Dart/P1010012.jpg
http://i16.photobucket.com/albums/b35/RpgMakerXP/Dart/P1010010.jpg
http://i16.photobucket.com/albums/b35/RpgMakerXP/Dart/P1010011.jpg
http://i16.photobucket.com/albums/b35/RpgMakerXP/Dart/P1010009.jpg