You have a couple of different options, you can either buy a receiver with a positioner, like the Echostar 3600ip, Technomate 5500ip, or Strong (the number escapes me), or you can buy a V-Box and any of a myriad of excellent DiseqC receivers which have perhaps a bit more decryption capability.
My system operates with an old PACE MS1000 receiver to move my dish.
I can't get parts to get it repaired, does anyone know were I can purchase a used MS1000 so we can canabalize the parts or use it if it is in working order.
Alternativeley can anyone recommend a positioner that will work with my system. I have a digital probe fitted to my old dish.