You want to get rid of cable AND You want to boost the signal. If you get rid of cable, what kind of signal would you be boosting?
1 You can watch TV on PC using a TV Tuner card, for which you need a signal source like Cable or terrestrial antenna (if it still works in your area).
2 You can use a DVB card for watching TV from dish antenna.
3 You can watch online TV on internet. It may be free but most channels need subscription.
For TV signal boosting in case 1 and 2, you would need a booster device like these : http://www.accessorystore.co.uk/acatalog/T...l_Boosters.html