Ok, we'll start with the video card first. Get a program like RivaTuner. Overclock in small several Mhz increments. When you get artifacts, bump your overclock down a little and you will then have your highest stable overclock.
As for processor, I'd luck up a guide if I were you, it can really help a lot. Go ahead and ask any questions about overclocking. As you overclock your processor, your RAM will overclock too.