re: What router should I buy?

I don't know your exact setup or what speeds you are getting, but things like channel, placement of the wireless router, etc makes a huge difference.

Theoretical speed and actual speed are very different.

For example, my wireless N devices on 5ghz get about 300Mbps. My wireless N devices on 2.4Ghz get 144Mbps. My wireless G devices on 2.4Ghz vary, lowest being around 18Mbps through a wireless bridge.