To the OP, you could upgrade your wireless access point to a wireless N device, but you would also have to ensure your devices (laptops, pc's, etc) also support wireless N to achieve the maximum available speed. However, as previously mentioned, due to the duplex nature of WIFI/CAT6 you will never realize the maximum speed via wifi. Wireless N, would, however ensure you have a faster peer-to-peer transfer speed (say to copy files and such between your devices, be it laptop, desktop, NAS, etc). If you are just trying to get the "maximum" speed your internet device (WAN) is capable off, then hardwired is the only real way to do so - and even then, your limited by other factors (mainly those which are controlled by the ISP).

Good luck.