iGO8 with Tomtom implant

I have put (ages ago) a replacement head unit in my Aero Vert anniversary. It came with iGO8 Primo system not impressed with the GPS and know that I can put Tomtom maps in there anyone know where I can get maps from please and is it just a matter of copying maps across on to SD card . Help would be good please
Numpty Cornwall (Fred)