since your not buying from overclockers i cant give you money saving recommendations, but i can give you general parts recommendations.
(dont say where you are getting stuff from, we're not allowed to mention competitors here)
the main thing you should do is change to a sandybridge processor. if you can afford the i5 2500K and a Z68 motherboard that would be great, if not the i3 2100 or 2120 and a H67 motherboard will do.
if its a gaming PC i would try to get a much more powerful graphics card, such as the 560Ti (and go for the i3 2100 to increase your budget for the graphics)
i would also back down on the case. $150 is a huge amount for what is essentially a mid range PC. something similar to the price of the coolermaster HAF912+ or CM-690 II lite will be more than good enough (unless your considering watercooling your graphics cards in the future)