Oceania (Australia, New Zealand & the South Pacific) - SYD Driver/Tour Guide Recommendations

We're disembarking from a cruise early in the morning in SYD, and we have to fly back to the States that afternoon. Our QF flight to DFW doesn't leave until 3:30 p.m., so instead of sitting for hours in the airport, I wonder if anyone out there can suggest a driver/tour guide who might meet the three of us at the cruise (with our luggage, so they would need a large car or a van) and show us quickly some of the highlights of Sydney. I would guess we would have 5 or 6 hours available, and you can see a lot in that amount of time with wheels.

Thanks!

Double posting (http://www.flyertalk.com/forum/australia-new-zealand-south-pacific/1225686-quick-view-sydney-need-guide-suggestions.html) is frowned upon here at FT. Good luck in Sydney!
Dave