From the WAN side, computers out on the Internet see your router's IP, which is the IP your ISP has given you (external IP). From the LAN side (the side that's connected to your computer), you probably see a 192.168.x.x address that your router has given you.
If you want to know the IP your ISP has given you, you can go to a site like
http://www.whatismyip.com/To see your internal IP, you can enter the command
ipconfig
or
ipconfig /all
from a command window and check the IP it lists for your ethernet or wireless card.