Setting up Airport Extreme for 450 mbps

Hello! I have an Airport Extreme Dual Band (A1354) and a new MacBook Pro (2011). When I connect to my wireless network the transmit rate is never higher than 166 - 200 mbps (in the 5 ghz band) According to some reviews (http://www.anandtech.com/show/4205/the-macbook-pro-review-13-and-15-inch-2011-br ings-sandy-bridge/11) you can get a transmit rate of 450 mbps. Is there anything special I need to set up in my router or my computer?

Thanks for your input!