Basically you need one of these <> or similar.
There are other manufacturers as well, and you just need to Google "Transformer Australia" and you'll get a list.
Choose a couple and phone them and ask to speak to someone in their technical department.

I repeat the advice of others. Do NOT, under any circumstances connect either the units themselves or the USA supplied leads to our 240v power supply. You might fry yourself as well as the lights.