|A bit of terminology confusion here. The Motorola SBG900 is in fact a wireless router. It has all the wireless facilities you need along with DHCP and NAT which is the main function of a home router.|
It only has one Ethernet port so if you want to connect more than one computer via wire you need a switch. You don't need another router, wired or wireless. It also has a USB port.
The one Ethernet port is supplied so you can connect a computer vie wires so you can configure the wireless, especially the security which is whole lot easier than trying to do it via a wireless connection.