AU shipments from my experience is that sometimes and quite often you can get a small package from the US to the AU in 5 days... if customs decides to flag it for inspection (which is random and I think somewhat computer generated) then tack on another 5 days for the process.
It can take a non-flagged package up to 7 days.. but in all my years of shipping to the AU I have only ever lost 1 package and I think it was USPS fault, probably never left the country.
Hold tight, your package is on the way.