I think you are talking about the actually AC jack that is soldered onto the logic board.
I have replaced many AC jacks on PCs, and its really rather simple if you know how to solder. As for a magsafe AC jack replacement, I have never heard of one breaking since the cord would unplug before an stress could be placed on the jack.
I would guess that something else is wrong with your logic board (other than the jack) or is just the power adapter that is bad. Good luck!