wireless 802.11n speed setting?

[bigpcman]

tc2.11
Using a dwa652 cardbus wifi card (ar5416/ar2133 atheros chip set) I have a wireless "n" connection established to my dlink 615 router. BTW the only way I can tell it's an "n" connection is by forcing the router to only operate in 802.11n mode. However, using iwconfig I can only set the speed to a maximum of 54Mbps. Anyone know how to set the speed to true "n" speeds like 135Mbps?