$30 gets you a cooler master hyper 212 evo cooler which is very good as well. it is big so be sure you have room in your case for it.
and for your system, the psu you have is plenty good enough. it is not suggested for high power gpu's and serious overclocking, however you have neither of those. plenty of power so it is not taxing the psu much at all. no reason to get a new one unless you wish to move to an unlocked cpu and start overclocking for records.