RAM and CPU share the FSB frequency. Your current RAM speed is the bus speed multiplied by the RAM multiplier (or ~ratio). Since RAM and CPU share the FSB, when you increase the speed/frequency of your CPU, you're also increasing the speed/frequency of your RAM.
What this means is, yes, you do have to overclock your RAM, sometimes, when overclocking the CPU. One of the reasons why you have instability after overclocking is because the RAM cannot handle the increase. This will all sound like gibberish unless you provide your RAM specs, or at least a link to it from newegg.
If you post your specs, we can try to help you attain a higher OC.