IP address?? We dont need no stinkin' IP address!
Seriously, you shouldnt need any kind of IP address to configure a router*
There are two types of ip address.
When you are connected to the router, you are part of a small network, and you have an ip address that identifies you, specifically, within that network.
(Think of it as the phones in your office or home)
You have an internal phone number or extension that identifies your phone and makes it unique amongst the other phones in the house.
The other ip address is the external IP address, that identifies you to the outside world.
How does your internal ip address get connected to the world? How is your ip 'translated' to the world ip?
That is the process called NAT Network Address Translation.
You could read up about it if you like, but its not really worth it, if all you need to do is connect to the internet.