I think the next MBP release will come shortly after Haswell, so possibly late next summer. By then, I wouldn't be surprised to see 802.11ac. Another good reason to wait for Haswell.
I have a dual band router - I think that the first wireless N in MacBooks were only 54mbps, I could be wrong - If you are using a more recent mac could you check yours - search for network utility in finder then select airport from the drop down menu.