So right now my computer is in the third floor of my home the modem Att installed is in the basement as far from my computer as possible. Right now I am getting internet from a Ethernet cord plugged into a Att Uverse Tv Wireless box. What should I buy to get a good connection to my 3rd floor computer I'm only getting 7 Mbps download speed when I pay for 21 down(my other computer gets 18-21 It is in the basement).