Gday Gramps,
How many hours do you have? If you have 1500 with 100 night, an ICAO(Australian) Commercial and current instrument rating, a US FAA First Class Medical, and around $1600.00 usd ( includes test fees and exam fees). Please check the website below for up to date prices.
You can go to
www.allatps.com they have training centres all over the States. You can get an USATP Multi-engine land.You will complete about 3 days study for a computer exam 80 questions ATPL theory and then do 2 prep flights and an actual ATP Flight test with an approved examiner.Aircraft will be a Piper Seminole no endorsement required as by US rules.
If not still send them an email thye may help you
REGARDS
SHEEP