Just discovered some bad rust where the bottom bolt of the control arm mount/trailing arm bracket connects to the frame, front driver's side - the piece of the frame there is really rusted, separating and halfway gone. At this point, the bracket is really only supported by the upper 2 of the three bolts. Frame-wise, nothing else looks rusty at all, but this part looks terrible... and definitely unsafe.

Also wondering what exact part that is - hard to tell in the diagram below if that's #4 (jack pad/jack support member) or #5 (rear extn front section/side member tie plate)? Or both?

http://www.tascaparts.com/parts/1993/Volvo/240/Base?siteid=213668&vehicleid=97673&diagram=9703590

Any idea of how much in labor this would cost to fix at a typical body shop? Besides the carpet, does anything else have to be removed from the interior to weld this? I plan on offering to take out the seat, carpet etc and order the parts myself from Tasca if that will save me $$$.