i and many other 240 owners feel your pain. I am dealing with this even as I type. If you have the ability to weld, cut it out, use reasonably heavy sheet metal and weld it in then protect with the best stuff you can find. If you can't weld, like me,start asking around. Most body shops do not want to do this kind of work as they cannot gaurantee for the life of the car like fixing a ding in a fender. In previous areas I ahve lived, finding someone to fix rust proved impossible. I am currently in Portland, OR and the first body shop I stoped at, yesterday morning, referred me a guy who they said was good and I already have an estimate. Hopefully you have luck similar to mine.

'87 240 dl wagon rust bucket