Dell Optiplex 755 Small Form Factor CPU Fan

My Optiplex 755 SFF has a stock CPU heatsink which, I know, provides for limited heat dissipation. I would definitely prefer to have better cooling, and am thinking that anything other than a plain heatsink (such as a fan) would suffice. My question is,

Are there any CPU fans that are compatible/fit inside of a 755 small form factor case? 

I've looked up a few potential fans such as:

http://red-planet-trading.amazonwebstore.com/Dell-M8788-Case-CPU-Cooling-Fan/M/B005Y2DTES.htm?traffic_src=froogle&utm_medium=CSE&utm_source=froogle

...but I'm not sure if these do, in fact, fit in this case _ and if they are a better option than the plain heatsink I have now (if they provide for better cooling)

- Thanks!