First of all welcome Eug.. If you are looking for a r33, get a series 2 like Zoix said coz the series 2 looks much better stock than the series one stock.
I only recently got me car.. so check out www.carsales.com.au, www.carpoint.com.au and also www.tradingpost.com.au. There was quite a few 33s, when I was looking for a skyline as well.
On top of the mentioned sites.. do a search for import car yards in yellowpages.com.au most of them also have websites that is slightly out of date...
If your 18.. the insurance for a GTST will cost you an arm and a leg.. but some people can still afford it... :|
Last but not least.. Colors is not a major factor (it can be changed relatively easy), probably better off looking for one that you can afford that is in good/reasonable nick with good engine and things..
Just my 2c worth. Good luck to your car hunting dude and once again welcome.. :wavey: