Hi, I have a similar setup from early 2010. 1st of all your psu has a 7 year guarantee (if its a good corsair). I am not sure why replacing it is so urgent since everything is working properly. As I read someplace, if it's a good psu, it will fall "gracefully" without endangering the other parts.
2nd, your cpu can be easily overclocked @ 3,6 or 3,8 or even 4 ghz with a proper cooler and it can handle any gpu without problems/bottlenecks.
Cheers