There are plenty of money exchange bureaus in and around Sydney. When you first arrive at the airport you will find 6 Thomas Cook bureaus, open everyday from 5.15am until after the last flight.
In the city itself you can find another Thomas Cook on Pitt Street, in Queen Victoria Building on York Street, and Kingsgate Shopping Centre, Kings Cross. They are open Monday -Friday, and also Saturday mornings.
However, there are a number of exchange bureaus which are open everyday. They can be found at the following places:
Open: 8.00am - 8.00pm
Open: 8.00am - 10.00pm
Springfield Avenue & Darlinghurst Rd junction
Open: 8.00am - midnight
There is also a money transfer system in Sydney offered by Western Union Ph: 1800 501 500. They can transfer money from around 150 different countries.