The 192.168.0.2, 3, 4 are ip address for your home network. Dude when you login to gmail don't you see at bottom, Last logged in Some_Date from XXX.XXX.XXX.XXX
Depends on ur ISP still. They might give you a Static IP Address or a Dynamic Address for your Server machine. You are most probably using 2 network cards. One for the modem and the other for your lan. Your server machine will show you 2 different IP address when you run the ipconfig command in dos prompt. You can't maintain your ip address for the network card connected to the modem, the ISP can.