Welcome to SAU Tyran.
There are too many variables to be able to answer your question like...
* there are skylines and there are skylines
* we don't know how heavy your right foot is
* the state of tune
* it might have turbo/s or it may not
* how much fuel costs in your area
* insurance varies contingent upon your driver history + your suburb + the type of skyline
* do you drive in peak hour traffic
* automatic Vs manual transmission
* how old and tired the engine is
* driving just yourself or up to 3 others
* registration costs are different according to state
* CTP costs are different according to state
* if you don't own the car outright, the interest on a loan will vary
We can only give you a ballpark figure if you tell us what you're diving now, and also tell us what that is costing you per year; tell us what particular model you're interested in - and perhaps, just perhaps, we can offer you a comparison.
Maybe you can answer some of the above questions too?