If you have manual controls, to fit the digital climatronic is much more than the display, there's various motors behind the dash which will currently be missing or controlled by physical cables.
Its possie, but not easy and probably quite costly.
I'm not sure the display can be used on its own.
To help you find more info on google etc I think you have 'climatic' system, the digital one is known as 'climatronic'.
Jas