The answer is in two parts.
Firstly, in regards to the website and hosting...
There will be a "Choice of Law" clause in your contract with the site provider (or host).
Any action you bring against the site provider would be under that law of choice.
That might not be Australia.
Which means, yes, you would have to sue them in Ireland, or Ecuador,
or the USA, or wherever you have agreed to.
For the transactions you do while in Australia,
it's about where you are.
Absent any express choice of law clause in the contracts you make with your customers
you can expect to be bound (and, indeed, protected by),
the law of Australia.