Right, so what you've got is part of two different systems. The wiring diagram above shows the two alternate setups, one for Australia and one for everywhere else. The wiring harness in your car is the Australian spec. You'll see the pin configuration and wiring colours on that plug match what's shown on the wiring diagram above for the Australian region. The signal wires from that plug don't go directly to the antenna, it'll go to a grey connector behind your passenger side kick panel, which if your 80 never had a power antenna won't be connected to anything.
You basically need to decide which end result you want to aim for. In my Australian 80, which also didn't have a power antenna at manufacture but I added it later, I have a modified version of the Australian setup. I kept the power antenna ECU, as it makes the antenna go up and down automatically when I turn the head unit on/off, and it remembers the height I left it set to, which I like. I ditched the "Auto" functionality to try and change the antenna height automatically though, and just went with manual up/down buttons, so I set the height and it stays where I set it, apart from going up/down automatically as the head unit turns on or off. If this is what you want, you'll need to source an antenna ECU (also called auto antenna relay, but ECU is more accurate here), as well as a different power antenna, which also has a four pin connector to report on the antenna height as well as the two pin connector to control the motor. If you look in your engine bay, you'll find this other four pin connector coming off the same harness as the two pin connector you've hooked up. The relay and antenna are possibly functionality identical to the ones on late model Lexus LX450's, which also had this kind of power antenna config. Apart from that, you're looking at wrecks in Australia.
The other option is to keep the antenna you've got, and rewire the switch to work the way the power antenna did on 80 series models outside Australia. For that, you've got the wiring diagram above again. You'd have to change some pins in that plug to work with the switch you've got, connecting the signal wires to the antenna motor, probably by bridging them at that grey plug for the antenna ecu where they all come together. You'd also need to take a new power run from the CIG fuse to the switch as shown. Getting a wiring pigtail for that plug with the extra pin from a local wreck would probably help. That would be the cheaper and easier option. It depends how comfortable you are doing wiring work though.
