well you're overclocking your cpu, I say yes get yourself a better heatsink. I'm using Thermalright SLK-947U with 92mm Tornado @ 2900RPM. Get Thermalright SP-97 if its compatible with your motherboard, or a Thermaltake Volcano 12 extreme this one comes with a fan 🙂
all I can tell you that it's better to cool an overclocked CPU using a strong heatsink then the stock sink