You will need to make arrangements with a bank for a letter of credit. Then you will need to make arrangements with a import/export freight forwarding company to transport the car from florida to australia. Upon delivery of the car to you in australia, the freight forwarding company would forward the documents showing they delivered the car to you to the us correspondent bank that is processing your letter of credit from the australian bank. Upon receipt of all documents stipulated in the letter of credit, your australian bank would release the money to the us bank who would then forward the money to the seller. It's sounds complex, but is really easy. But you must use a bank with an international department.