Pinnacle 310e fitting to a Vast satellite system decoder

I have a 310e model which has been very good up to when the terrestrial TV was replaced by a sattelite system,now I have to find a way of connection to a Vast decoder box (STB) I have looked at splitters and this has to be the way to go (thinks) at the moment I have a satellite on the roof with a cable connection sticking out of my room wall (screw type fitting) from this wall connection A cable goes to the decoder, and from the decoder, the LCD TV is connected by a USB cable. all work fine, and can get all TV signals from sydney to Perth and all the northern states, MY Q is ___what kind of a splitter am I looking at,what I mean is, does it have to be a certain Mhz or min standard ( there are many differences when looking for a splitter ) : is there anyone had to use this kind of hardware to access a satellite connection ? ___and further still !!! can it be done, If I can get a signal on a TV then I should be able to get a signal onto my Computer monitor, thanks to all
From Bill in Buxton. Victoria. Australia.