The CM EP+ 550W is not a good quality PSU: http://www.hardwaresecrets.com/article/Cooler-Master-eXtreme-Power-Plus-550-W-Power-Supply-Review/969/9
It can't deliver much more power than the Elite series. Of note is that the Elite series from CM doesn't include a 430W unit; there are a 400W and a 450W.
I would personally go for the Corsair Builder CX430: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026&Tpk=cx430
Are you in the US? If not, then list some sites that have PSUs you can get and we'll make recommendations based on that.