Ok Just a little information for you to think about.
Flight time - from Los Angeles international Airport (LAX) to Sydney International Airport (SYD)is 14 to 15 hours. Qantas and Virgin Australia offer non stop flights. Personally I always fly with Virgin Australia. Qantas has a very good reputation.I have heard a lot of good things about Air New Zealand but they do not offer direct flight, you will end up with a layover in Auckland.
Flight cost - from LAX to SYD US$1500 to $2000 return for late march early April 2015 (information taken from
webjet.com)
You will need to factor in your own domestic flights but I'm happy chat with you about that if you need help booking it.
Also you may consider a bit of touring and may need to fly home from a different city. Flying between Australia's major cities can cost anywhere between AUD$80 & AUD$400 depending on the distance and time of week.
Exchange rate - Subject to swift and often pycotic change but at the time of posting this it was pretty good. Currently US$100 will buy you AUD$107 (information taken from
ozforex.com.au Australian Foreign Exchange Services).