hi tim,
the best advice i can give you is to register with the RTC. there is a voluntary donor registry, and if you can remember your donor code, or any other information like that, you are more likely to find a match.
this is the site.
http://www.voluntaryregister.health.wa.gov.au/by the way, it is wonderful that you havent been turned off coming forward. it takes alot of courage, and it makes you so much more admirable in the eyes of us who cant find our donor fathers.
www.donorsiblingregistry.comthere is also the donor sibling registry where you can leave any information regarding your donations and your information.