hey mate, you're a bit like myself, although I wanted a 350Z first up until I learned that they are on the P's restricted list. My mate let me drive his R34 GTT and I've pretty much been in love with the R34 since. For beginners, as many people have told me, don't bother getting a Skyline but I ignored them and got myself a 98 R34 25GT. I rekon they are great for starters who wants to lead into tuning it up and things like that. If your not into the later model skylines like the V series, the R34 GT would be the way to go IMO. They cost about $9-14K on average. Picked mine up for $11K.
Get yourself a R34 GT and when you get your fulls, get yourself a GTT or GTR if you have the cash. I too was thinking of doing up my car but it's not worth pouring $5K+ in coilovers, brakes, wheels etc since you can't do anything to increase performance yet.
I'm happy with what I've got and I'm planning to sell the car once I get my fulls. When it's gone, either I get myself a 350 or a GTT or GTR. I suggest you do the same way.
Where abouts are you from in Sydney?
Here's mine:
http://www.skylinesaustralia.com/forums/index.php?app=core&module=attach§ion=attach&attach_rel_module=post&attach_id=390699