I strongly agree with Jo on just running a new wire. (The method he was describing was the simplest.) When you get the Materials he requested, you open up an existing phone jack, and after exposing some bare copper of the ends, screwing the 4 conductors onto the screws of the matching colors. Run the wire to the location you want it. and exposing some copper (aobut a half inch) screw the same colors on to the matching colors of the jack.
Another Option you might consider. I've seen them at Wal-Mart and Radio Shack, are the wireless units. They cost 70 bucks, but you plug one end into a wall socket, and a phone line somewhere in your house. You plug the other end into a power outlet, and your direct TV into it.