147.150 + 600, 91.5T is a good repeater in and around Sydney. Someone will normally answer you if you call. 1273.00 +20MHz is at the same site (Chatswood) in Sydney and is also usually monitored.
You wont see much snow unless you go to the Victorian, or NSW Alps and their associated ski fields. If your lucky you may see a dusting of snow that wont last a day or 2 at most in the Blue Mountains W of Sydney. If you want to see snow then I can recommend Mt Hotham in Victoria. There is a lodge there that is run by one of our resident Mountain Goats. Brian will set you up good and proper for a lifetime of activations amongst 10 pointers with 3 winter bonus points.
Send me an email and we can figure stuff out re when you are in Sydney.