No...you need a HD box...Apart from the Sky one that costs �299 I don't know of any others at the moment...
Have a look at the back of your box...If you've got a HDMI output...which I'd bet money on that you don't have one....Then you've not much else choice but upgrade. Sorry. Perhaps wait until after christmas in the new year when they'll be slashing the price of the boxes..I'm sure they will.