What Wattage Power Supply Should I Get For This Build?

That EVGA 500W will work just fine for your needs. If you must choose another I would recommend choosing any other 80+ bronze PSU that is at least 500 watts and is a reliable brand like Corsair, XFX, Seasonic, etc. Other than that the PSU you linked is fine.
 
kk thanks. Is that the minimum you need in terms of wattage. Of course i still want max performance without over clocking. my budget is around like £450