I think the amount of money you have already invested leaves you with only one thing to do, frame replacement. Your only real choice is buy or build, if you own a decent mig welder and can fabricate you would be money ahead to build your own out of retangular box tubing, if not, after market frames are relatively expensive, but still cheaper than any other option. (willys-overland had some stock frames for $800, but i do not recall for what years).
good luck jjc
good luck jjc