How can I get more TV channels on my PC?

I have a USB DVB-T Tuner. Using my normal ariel connected to the USB I only get 29 channels (incl. Radio..actually...mostly radio.). I get all the freeview channels from my Digital box. I am guessing that the digital box has a built in signal booster and my USB doesn't? So does this mean I need to get a signal booster to connect to my ariel for use with my PC?