I bought a £10 aerial off the bay and hell it has worked vrilliantly. Mind you it's much bigger than I expected. It's one of these and it has boosted my signal so that it sounds great rather than a bit dodgy.
http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=33220&doy=1m9
http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=33220&doy=1m9