Definitely change that PSU. Cooler Master makes terrible PSUs, they’re pretty much a taboo on most tech sites / forums. Higher end models of Cooler Master are viable BUT for that price there’re already much better option.
Get an Enermax 650w 80+ if you’re tight on budget, or go for a Corsair / Seasonic if you’ve got more to spend.
As for GPU, don’t settle for anything less than a 7950 or a 280.