I'd start with Vendor-Neutral certs that are recognized internationally. The basics are a good start, like CompTIA's A+. That's composed of two parts, (Exam 220-801 and 220-802), and signify the equivalent of 6-months to 1-year of field and bench experience in installation, preventative maintenance, networking, security, and troubleshooting. Looks like exam vouchers are AUD191 each (you'd need 2). You can take both exams the same day, or at a different time. They have a number of options for preparation, including their own Certmaster online tools, as well as Third-party textbooks, online resources, books at the library, and training seminars/boot camp events (those can get expensive). It really depends on how you learn best. The exams are adaptive in nature, so you're given medium difficulty questions, and if you pass them, you get harder ones, and if you miss them, you get easier ones (similar to the GMAT for entrance to an MBA program).
If you wanted to stick with CompTIA for a few more, you can look into Network+ (exam voucher AUD280), Security+ (exam costs AUD303), Server+ (exam voucher AUD280), or Linux+ (exam voucher AUD175).
Most of these certs are good for three years, and to maintain them will require taking the updated exams or enrolling in Continuing Education programs to keep them up.
It's similar for Microsoft certifications and Cisco. You'd really have to make a few decisions on which direction you want to go ahead of time (development, networking, or hardware support), as that will help you narrow your focus and save you some time and money on training and certifications. Certs don't teach you how to do the work. They supposed to prove that you have baseline skills to do the jobs in the fields they cover, but in actuality, like any other standardized test, they just prove that you know how to pass the test.
More info on CompTIA at http://www.comptia.org/
http://www.comptiastore.com.au/Articles.asp? ID=261&category=learning
(when you start looking at pricing and prep materials, you may have to manually browse to global or Australian site to get customized pricing).