A quality 450W is more than enough. Definitely return that Ark PSU, I can't even find the OEM on it which means that is is going to be complete junk. Go with Seasonic, Antec, Corsair, etc. Give me a budget for your PSU and I'll recommend you one.
I mean i dropped $600 + on the parts, i could do between 30-60$ on the psu.