Please advise...Living in UK, Hold Oz PR, want to add wife!

OK the cryptic subject explained in more detail:

I am a UK citizen, currently living in the UK. I hold a Assie PR status valid until end of 2011. My wife is Colombian and in the UK on a UK spouse visa.

We are thinking of heading back to Australia in about 18 months, so begs the question, what is the best way to go about it.

Can I apply to have my wife as de-facto on my Aussie PR from outside Australia? If so, this is the normal de-facto/spouse process?

Any other suggestions welcome.

Thanks in advance!

spouse visa, start at http://www.immi.gov.au