Congrats on your trip to SYD!! (my favorite city!)
Like the above posters have said, if you let us know which flight you're on, we can look at the available seats in E+ for you. Without status and if the flight isn't oversold, the chances of getting an E+ seat complimentary are slim. However, during check-in (either online or at the airport), you are usually offered to "buy-up" to E+, or better yet to Business Class. I don't know what E+ usually sells for, but Business upgrades are usually around $700-$800 one way.
I also recommend checking out seatguru.com and seatexpert.com for more details on UA's 747 seating.
Again, congrats on winning a trip to SYD!