I agree that you need a second opinion to make sure this converter is bad. If it really is, you need to find out why so that you don’t kill the new one for the same reason. I assume the check-engine light is on now. Was it on for a long time before you had this checked, by any chance?
Even if you need a new one, there’s no way I’d dump a 2006 car because of a $1,500 repair, assuming the rest of the car is in good shape.