Science Of Speed

I am in the process of wiring in my G1 LEMV5 ecu which I purchased with a toyota 3sgte engine for my ST185 GT4 Celica. The engine was previously used with this same ems for a rally car, and I have changed the cams and turbo, and would like to re-tune based on my setup and requirements. I did not receive any tuning software or hardware when I bought the ems and I now need a cable for the laptop tuning option and the software. I would like to know where I can purchase this, especially the cable from the ecu to the laptop (serial or usb....does not matter). Thanks.