The CM Hyper has been enough for me to get to 4.8. The cooler is great. As for the PSU 650 is great. If you want a really nice 80+ PSU, go for the rosewill Capstone-650. If you want to crossfire and be safe, get the 750. This psu series has been taken apart and graded by multiple reviewers to be great. Here is one, http://www.techpowerup.com/reviews/Rosewill/CAPSTONE-750-M/10.html
Oh, and btw, if you're not willing to pay for an entirely new system, buy a quality PSU. When that thing dies out, your system dies out. A 30 dollar PSU will never be a good option for use on a machine meant to last any good amount of time.
Oh and I forgot to mention, higher clock speeds are achieved through a quality board (which you have) fed by stable power coming from the PSU. Then you keep the temps down with an aftermarket heatsink. Without the first two, you're screwed.
You obviously plan to overclock, so I wouldn't push a 500 watt system requirement for the amd card with a 550watt psu. You always want to buy a little more than you need. And as for the psu, honestly any corsair, rosewill, seagate, or any other good, big company will be a good choice for PSU. If you have to, just use the i5's dedicated graphics until you can afford the graphics card that way you get the good PSU and are still able to use the computer for basically everything but playing games. Even then, the IGPU is actually pretty good. (Of course not 7850 good, but playable). A quality PSU that can support your hardware in terms of wattage and amperage is by far the most important part, gimping out on it will be your biggest mistake when it fails within due time.