A few great Wineries are:
Tyrrells wines: (Great Semillon and Shiraz)
http://www.tyrrells.com.au/
Tulloch Wines: (Great Verdelho and Shiraz)
http://www.tulloch.com.au/
Tempas Two: (Great Pinot Gris)
http://www.tempustwo.com.au/index.php
A good place to see and stay is the Hunter Valley Gardens. Enjoy the trip.