How to select the heatsink/CPU Air Cooler for a processor?

I have AMD Phenom II X6 1055T processor and MSI 890 GXM-G65 AMD 890 GX motherboard and 2X2GB Corsair DDR3 1333 Mz RAM and Elite 430 Black Cooler Master PC Case. The CPU fan rotates at 7000 rpm when the temperature of the processor is 51 degree Celsius and the fan is so loud. It scars me so much. I feel i might burn my processor. I have not even overclocked it. I just play counter strike. I haven't installed graphic card for now. I will buy a graphic card a month later. So am looking for a good heatsink. I dont want to reduce the life of my processor which was very costly for my budget. I googled so much but could not find the heatsink for my processor. Can anyone suggest a good heatsink? I want to work on my PC without having any fear. It always flashes in the back of my mind that my processor is gonna burn coz the CPU fan gets so loud just for very less load. When i switch on my AC and open the PC case, the temp drops down to 46 degree celcsius and fan rotates at 5000 rpm with low noise. I cant keep my AC on forever. I checked my stock heatsink and its installed properly i guess. I checked it it twice. It's fixed firmly. How do i solve this problem?