Welcome mate,
Nearly everyone will recommend Motul 4100 Turbolight oil for your motor and it can be found at Repco and Autobahn. Most places wont have a parts list for our cars, but if you can find the part numbers then they'll most likely have them or be able to get them in for you. try using the SEARCH TOPIC in various threads if your looking for this information as it had been talked about so many millions of times that it should be easy to find. servicing your skyline is so simple that a baby could do it blind folded! if you need some help just ask and most of the guys on here will be happy to help guide you through it. as for the shocks, $700 a pair is a little steep. there are only 2 places in canberra to go to for suspension and that is Inline in Qbn or Capital Steering and Suspension in Fysh. i think i got quoted about $600 a pair for Bilstein's about 4 or 5 years ago....
hope this helps...