1999 Toyota 4RUNNER suspension problems

As I was driving down a 4 lane highway, the steering wheel suddenly jerked out of my hands to the right. I was unable to turn the steering wheel back to the left to correct. The roads were wet from an earlier rain; there was no standing water, no pot holes, or other visible defects in the road. I was in the left lane, traveling about 60MPH.

Original owner, not located in the "rust belt" took 4runner to exhaust shop to have a new exhaust put on and once underneath the vehicle you could see that the frame has completely rusted through near where the trailing arm brackets are and on the inside/underneath of the frame. The rest of the frame is in great condition because the 4runner has been take care of and maintained. There will be about a 2 foot section of frame that will need to be cut out as well as new trailing arm brackets to be cut and welded in.