well i am not sure what intel is going to produce!you may wait and the new cpus wont even fit to your system i always say think about now!but in this case your system can handle pc games cause the quad!so my advise is to wait!
If you can live with how your current system performs, I'd wait since it's only a couple of months away. There probably won't be huge performance gains, but wouldn't want to build on a dead platform (1155) this close to the next socket.
Haswell is not likely to be a major improvement in performance over Ivy Bridge since the focus is to lower power consumption as much as possible so that some Haswell CPUs can be used tablets which is the current growth market. The desktop PC market has been contracting for a few years, and laptops sales have slowed down to mid-single digit.
The biggest improvement for the desktop Haswell CPU is the Intel HD 4600 graphic core (GT2) which is estimated to be a 20% improvement over the Intel HD 4000.
The increase in CPU performance (assuming same clockspeed) will probably be around 6% - 8% over Ivy Bridge. Not a significant improvement. But that is just a guess. Everyone needs to wait for Intel's NGA (Non Disclosure Agreement) to expire before official reviews be written.
Anyone breaking an NGA could lead to something as simple as no more future products provided by Intel for preview/review or up to something as serious as a lawsuit.
The biggest improvement is the supposedly named Intel HD 5000 (GT3) which will be exclusive to mobile CPUs only. The Intel HD 4000 has 16 shaders. The Intel HD 4600 (GT2) will have 20 shaders and is estimated to be a 20% improvement over the HD 4000. The HD 5000 (GT3) will have 40 shaders. Current guess-timates ranges from between 50% to 100% more powerful than the Intel HD 4000.
While there are 40 shaders, there are some speculation that Intel will be lowering the core clockspeed (compared to the HD 4000) in the iGPU to lower power consumption.