3 choices..
1) run a standard aerial cable from the sky box to the upstairs room and connect it to the RF2 output on the back of the sky box and tune the tv into the signal (you can get a sky magic eye too that will enable you to control the sky box from upstairs)
2) get a wireless video sender (some will send the remote signal back the other way so you can control the sky box from upstairs)
3) get sky multi room which means another sky box and another feed from the dish to the upstairs room (there is a monthly charge for multi rooom)