Sue, I have to go with Zeus's comments. You drove all the way back home and your lower control arm did not fall off demonstrating the reserve capacity of the arm. The arm is cracked and that has to be addressed, if you can't find a new one beat the old one in shape and weld a section over the distressed section. If you take out part of the frame and weld in a new piece you will have a patched(weaker) frame that will lower the resale and originality plus have a good place for rust to start on the inside of the frame. Just use a stock lower control arm, if you get a beefed up one the next time the frame or something else will break. If the new arm doesn't line up, that is where the frame shop will come in.

Mike