|If you were on DSL you could get a DSL Router with built in Modem/Router/Switch/Wirless Access Point, everything in one box.|
I have never seen cable routers with built in Modems so at the very least you are going to need a cable Modem and a router. Most routers have built in wireless access as well as a switch for wired access. If you want to connect the printer to the network, wireless or wired, you will need a printer with a built in network interface. Otherwise you will have to connect the printer to one of the computers and configure it as a shared printer. You will not get a single device to do everything you need.
also looking for N-cable speed
I take it you mean 801.11N which is a wireless specification, nothing at all to do with cable. Whether you can use 801.11N is dependent on the router you buy and the network interfaces in the computers.