Ah well in that case, there's really no need to buy anything. With a halfway decent mobo, it's possible to overclock to 3.2GHz on that chip while undervolting by a fat margin and as a result run cool under max load with the stock Intel fan at its lowest speed. That's just a baseline suggestion, it can be tweaked up or down depending on the quality of the VRM. Regardless, the bulk of the performance increase will always come from pushing the FSB.
To put it into quick perspective: on my system with the same CPU, with the CPU at 4.4GHz and the FSB at 360 it was significantly slower than with the CPU at 3.8GHz and FSB at 440, even at SuperPi which is a CPU-heavy stress test. On a P45 chipset, 360 is doable even with an awful stock heatsink and if the FSB strap can be adjusted that bodes well for shitty RAM.