Get this 380W Antec Earthwatts: http://www.canadacomputers.com/index.php?do=ShowProduct&cmd=pd&pid=027538&cid=PSU.731
Your GPU sips juice; it isn't a gaming card. Even if you wanted a newer HTPC card like a HD5450, you wouldn't need a bigger PSU.
Just be aware this PSU doesn't come with a power cord, so save your old one.
Edit: As to noise, I installed one just a couple weeks ago in my Mom's PC, and had to double check that it was on when I first flipped the switch. It is almost inaudible.