the router should set itself at 192.168.1.1, which I don't know if you can change.
Let it do DHCP for your computers, as the default range should work fine unless you have another device that has to use that IP range. For example, I have my router set at 192.168.1.1 and my two computers (dynamically at first but now statically) at 192.168.1.100 and 192.168.1.101
No one on the WWW should be seeing these addresses, so it only matters to you.