memory corsair pc3200

Hi guys well just wondering what i should do I have a stick of corsair xms pc3200 cl2 512mb running win XP pro overclocked at 165fsb with a PIV system asus motherboard but want to get more memory put don't want to lose my overclock should i get cosair pc3200 or pc3500 512mb please guys help me out here Thanks

I have the 3200 and check out my sig to see specs. This RAM is easily good for MUCH more.