Given the context, I'm assuming you've bought this from some OEM vendor such as Dell or something.
The graphics card you mentioned is one that's built into the motherboard. This poses 2 problems:
1: the graphics card cannot be overlocked at all. If you can even try, I wouldn't recommend it since the cooling system on the graphics chip would not be sufficient, and this would cause all sorts of problems on that same chip (which unfortunately controls just about everything else on the motherboard).
2: the motherboard in question wouldn't be built for overclocking. Overclocking facilities will be minimal at best.
Also, the CPU in question comes with very limited cache, which will not be very efficient doing anything you want anyway. (ie: its crap).
Please note that overclocking isn't the panacea for crappy hardware: you usually have to start with decent hardware (note that decent doesn't mean high end) to overclock. Read my FAQ for some info about overclocking, and bear in mind that low end hardware is usually a whole different architecture altogether (i7, i5(I think), C2D all have different architectures, not to mention the dual core and quad core varieties)
