The first thing you need to do is load the BIOS and look for the CPU multiplier and base clock. The calculation of multiplier x base clock gives you the overall clock speed of the processor. For your spec, this will probably be 34 x 100, which equals 3400Mhz or 3.4Ghz.
For Intel "k" series processors, leave the base clock at its default setting. Changing this will overclock other components, which you don't want to do.
You should be able to increase the CPU multiplier in increments of one; 35, 36, 37, etc. For every single multiplier increase you make, your clock speed increases by 100Mhz. Your motherboard should give you this information in real-time. Start with a 4Ghz overclock and run a Prime95 torture test for about an hour so you can monitor the CPU temperature (use Realtemp or HWmonitor for this). If everything looks good at 4Ghz then you can go to 4.1Ghz, 4.2Ghz, etc until you reach a safe (and quiet) limit. I recommend staying below 70° C.
When you overclock you should also adjust your CPU voltage (VCORE), but that's another story altogether.