I'm afaid that you most probably need an outdor aerial for Freeview but you MAY get away with a loft aerial. You can buy all the stuff from DIY stores if you DIY it. You don't say where you are but a 'wideband' aerial will suite most people - unless you are in a marginal signal area. To find out where to point it roughly look at your neighbours' aerials, then use the TV set as a meter. Turn the aerila slowly until the signal drops off, then turn it the other way until it drops off then centre it between the two points.
If you have one installed by a professional get one that is CAI registered. They'll charge about £100 - £150 including the parts.
Terry
October 2006