You cannot use both the wireless and wired connection at the same time. If you really want to make it work using your Gigabit NIC's, it gonna be a little expensive because you will need an Access Point and a Gigabit hub/switch. Your broadband as you mentioned is located in a different area of the house. But are the 2 computers close to each other that you can have them running thru a wired connection? That will be the only way to make use of your Gigabit NIC's and share the internet connection at the same time without having to use a passthru connection, meaning both PC's has to be on for the other pc to gain access to the internet.