My club in Melbourne might be for you - Melbourne Argonauts (www.melbourneargonauts.com).
We're (I think) one of only two fully independent gay rowing clubs in the world. Row at Albert Park Lake and can tell you is a top club - friendly members, good competition opporutnities, reasonable fleet.
Otherwise check out Glebe rowing club in Sydney. Met a few of these guys recently at Outgames in Melbourne, and they're great fun.
Welcome to Australia - see you on the water sometime!