If you want to determine your website address then you will need to register a domain name.
.au domain names require business name registration and are registered for no less than 2 years.
If the name you want is already taken then it may be for sale. You could check it Netfleet
|Register your Domain Name Today!|
|.com.au -.net.au (2 years)||$72|
|.com,.net,.org,.biz,.info (1 year)||$27.50|