If you're looking for Business Case Studies for your assignment, go to www.afrbiz.com.au which has a list of companies to choose from, with information compiled by the Australian Financial Review specifically for students.
Also, got to the website of your chosen company, where you will usually find plenty of useful information, including company histories and Annual Reports.
You can also get recent news stories from the Australian Financial Review (available daily at HJ Daley Library) or via our newspaper and magazine article databases at our Reference Databases webpage.
Good luck