Are you able to to see the network name on the Nook Reader? Do you have any other device that gets connected wirelessly @ home? If you are able to see the network name then what happens when you try to connect?
In your wifi settings on your Nook there should be something to the effect of discover new networks, or find networks, or add new network. Click on whatever it says and you should see your 2Wire network listed. When you select "Connect" it will ask you for the password. The password is located on the side of your RG or Residential Gateway. Once you enter that password you should be good to go. Let us know if that does or doesn't work.