I'm no expert here, so I can't help with specifics, but I do know the more you OC it the more you risk frying it. How new is it? From what I understand, the newer ones can handle it a little better, but I still wouldn't recommend upping it more than a little. When I was having trouble playing Aion we just upgraded my processor. You can do that. A good computer shop should be able help with finding you an upgrade and putting it in for you. I don't remember how much mine was, but it wasn't too bad. The individual parts aren't that expensive, except for motherboards.
To look up your system, I believe you go to start, system tools, and then system information. That's how it works on Windows 7 anyway.