Couple things:
All CPUs, at least from what I've learned with Sandy and Ivy Bridge, at some frequency, require a lofty jump in voltage, it sucks, yes, but is a necessity if you want that increase.
Instead of buying another fan, I'd get a different cooler. And hell, you're working with a HAF 932! I have a HAF X 942, so I know you have more than enough room to work with. Depending on your budget, I'd try and get whatever is the best you can get, I'll bet your temps drop a fair load. Coolers I'd suggest you consider if you can:
Noctua NH-D14
ThermalRight Silver Arrow
Corsair H100i (the i version is awesomerrrr)
Zalman CNPS 9900 (any of these are good, and a bit cheaper)
Corsair A50 (the A70 seems to have disappeared from the market...)
Noctua NH-C14
NXZT Havik 120/140
There's others, but I felt this was a good enough list. :P Also, you can see the temps I get with my Zalman CNPS 9900ALED.