The power connector on the bottom isn't stuck in place. It's on a metal frame - you'll note that to the sides of the mating molex connector there are two circular pins with flaps on them - like so

If you grab the flaps on the side with pliers you can force those little circular supports back through the metal, and the connector will come right out. Just be careful - if you screw up, you're going to have a hard time mating the SMPSU back to the logics

Also if you need parts, a WTB request on the Trading Post on this forum can be most useful.