Take a look at http://www.smallnetbuilder.com/ and choose your router. As you have many device look for max simultaneous connections parameter. Also, you might need one or two access points if the router does not cover the whole house. If you look at current mesh network offerings, keep in mind that they are router+access points bundled togather. A god router should cover your whole house, but probably not on 5 gHz, but on 2.4 gHz. Your N600 (I asume Netgear) has 5 gHz. Try first and split your clients into the two different bands. But it will not keep up with that much traffic.