Hey leetrix,
You mean you got slow wireless speed, eh?
You might post your running config from RFS but first you should review your wireless design - channels, channel widths, powers, interferences, obstacles, client count, number of SSIDs, minimum basic rate... The issue might be there.
Have a look here as well:
http://divdyn.com/top-ten-tune-tips/
http://divdyn.com/moo-mimo/
Hope that helps,
Tomasz