Here is what I would do:
Bring the D-Link back, then buy a Wireless netgear router (I got mine for 50$). Then you will only need to buy one wireless ethernet adapater for 50$, and you can plug the computer next to your router into the router directly with one of the cables you have. Its definitly worth it to go wireless, I had a linksys router and had wires running all over the house until my entire house got flooded while I was on vacation. So now I switched over to netgear wireless router and I have had 0 problems with it. It took 10 mins to setup to.
ThePornPusher