I have our modem/time capsule on the 3rd floor in the attic. I have a cable running to the first floor for my aunts mac mini. I got her an ipad mini for christmas and want to give her my old Apple TV as well. the time capsule wireless signal is shaky on the first floor. its fast in some parts and super slow in others. So i was thinking about adding an airport express to extend the signal. Can I attach the cable from the time capsule that gos to the mini into the express and a cable from the express into the mini? I saw the new express has 2 ethernet ports but im not familiar with all the networking lingo. I just want to extend the wireless but keep the mac mini wired.