These instructions should help you out. By the way, do you have the manual that came with your router? If not, try here
From your router's manual...Using a Wired Connection
It is suggested for first time setup your Router that you used the wired connection method. It is simpler, and eliminates the possibility of error due to improperly setup wireless connection.
Step 1 Turn off all the hardware devices in your network, including the ADSL/Cable modem by unplugging their power supply.
Step 2 Connect the Ethernet cable of your ADSL/Cable modem to the WAN port of the GN-B49G.
Step 3 Connect one end of an Ethernet cable (provided) to a LAN port in the 12 GN-B49G High Speed Wireless Broadband Router side panel of the GN-B49G and the other end to the 10/100 Ethernet port of your computer. (It does not matter which LAN port you select).
Step 4 Plug the power adapter cord into the router’s power jack and then plug the power adapter into a power outlet.
Step 5 Turn on your ADSL/Cable modem. After verifying all the connections, proceed to Preparing Windows XP for the B49G.Continue following the directions in your manual.
Afterwards, you will be logging into the router, completing the setup (with a cable ISP you will not need any of that info you quoted from your provider earlier), and rebooting your router and computer. After that, your laptop should pick up the signal.
Hope this helps.