Is there any evidence that George Soros actually said "Destroying America will be the culmination of my life's work"?

This is the oldest reported instance of him saying it:

"Destroying America will be the culmination of my life’s work." Soros to The Australian.

http://theantiliberalzone.blogspot.com/2010/09/who-runs-our-government-and-owns-it.html

Can someone please help track down the source? I refuse to share unsourced quotes.