Logisys?? They offer some of the worst PSU-shaped objects you can find. They should NEVER be attached to computer components if there is any chance they will be connected to a live A/C power source at the same time.
What brand and model is the "470W" PSU?
A quality modern PSU has full range active PFC (no little voltage switch) and some level of 80+ certification for efficiency. Seasonic, Antec, Corsair, XFX, and Enermax/LEPA are among the better brands. Logisys, Diablotek, Apevia, and Coolermaster are not.
A 380W Antec Earthwatts would run your father's system just fine. If you think he will install a more powerful GPU, then you would probably want the 500W model. The PSU calculator at http://www.extreme.outervision.com/psucalculatorlite.js... can be used to estimate requirements.
Short answer: Get a 500W Antec Earthwatts and you're done.
Longer answer: Sometimes you can find a good deal on a Seasonic, Antec, or Corsair PSU. Most of them are 80+ bronze or better. I think the 430W Earthwatts would be a little small for a GTX560Ti, but anything 500W or bigger would be fine.