eh, how many pc's on the router? I run through wireless and the only time I ever lag is when my brother is on his computer. but as far as the router.... as long as your getting a good signal from it I dont think I would worry about getting a new one... I think the different ones just send a signal farther, dont really think its going to speed up your internet...
another thing is to make sure the wireless is secure so people around you cant connect to it.