About a month ago someone posted pages from an old manual showing how to brace a frame properly...
Edit:
Tried to find that post but couldn't so you'd never figure that one out...sorry...
I did use the search engine and there are actually quite a few posts in various threads about bracing the frame...maybe someone else can offer something better, but there is plenty of information on here...and also plenty of pics (that I recall) of frame patches...so you may want to use the search engine and just go through what's in there...search on "Frame Repair" or something similar...
you could also approach places that install springs or other welding shops...they might charge you quite a bit depending on the damage, but if they're experienced it might be worth it...otherwise...finding the info is only half the battle...if you have a welder and some steel you could probably do it yourself...