You can put a passive tower cooler on it.
http://www.silentpcreview.com/article30-page1.html
The site of the link focusses on making your pc system as quiet as possible.
I would recommend this heatsink:
http://www.silentpcreview.com/article842-page1.html
I have it myself and a run a overclocked q6600 at 3.3 GHZ 1.35 volts and the processor gets to a maximum of 65 degrees celcius when stress testing all cores with prime 95 the ambient temperature is then 25 degrees. I use a 12 cm fan which is inoudible at 1000 rpm i have my pc beside my bed and i dont hear it even at night.
Your processor at stock will dissipate about 30 watts (where my q6600 will diisipate 100 wats overclocked) so it is very possible to run your processor passive with this heatsink.
Read the reviews on that site and Good luck.