Don't see why the Autoleads PC7-103 cable wouldn't work. I'd double check the CD changer plug in the back of the headunit first though. Or even better, just call Autoleads technical. The guys there are really useful and know their stuff.
Uses the plug from the CD changer, so it's either CD multichanger, or aux(or iPod!) but not both.
Halfords are doing a bundle deal at the moment if you were considering a new CD player.
Pure 260Dbi single DIN headunit with everything needed to fit it and installed for £119. Optional £20 DAB antenna for digital radio too.
CD player, aux, USB, bluetooth. - Pretty good deal if you didn't fancy attempting it yourself.
edit: you'd lose steering controls and CD changer if you have them with the new headunit option