*EDIT* I assume you mean make it cheaper without losing any performance power?
Really......probably not. You're about as cheap as you can really go. If anything, I'd point out reasons you should spend more!
1. Decent aftermarket cooling for OCing
2. Replace that PSU, it won't do too well under stress.
These would be much better PSUs: All are quality units, ranked Tier 2 or better (http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html)
http://pcpartpicker.com/part/seasonic-power-supply-s12ii520bronze
http://pcpartpicker.com/part/evga-power-supply-110b20750vr
http://pcpartpicker.com/part/xfx-power-supply-pro750wp1750snlb9
The EVGA & XFX units at 750W are totally overkill, but minor price differences - so would be worthwhile if only from that sense alone.
So, ultimately I failed at the challenge to make it cheaper.