Well Newegg's PSU calculator calls for at least 526 watts.
http://educations.newegg.com/tool/psucalc/index.html
So get a 550W one like the Antec BP550. Try getting your PSUs from reputable manufacturers as poorly made ones can fry your parts.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371016