From what I have heard, graphics is one of the most expensive areas for gear. 2G RAM might be ok, but more is always better. The CPU is less important but I guess its fair to say that you'll get the best you can afford. Several websites have PC builders on them, like ascent.co.nz, or the dell site. They may help get an overall picture of price. If your wanting to put the parts together yourself, pricespy.co.nz is your friend.
The graphics card should probably do it, but you need to think more about what sort of graphics he wants to do, a gaming type card is not always the best solution for more advanced 3D work. The other aspect which you didn't mention is the display. Nothing like squinting at fine details on a small monitor to make your work more challenging. Also the card and monitor should make a good team... I'm not a graphics expert, but perhaps this will help give you a frame of reference. Others may be able to suggest specific gear. All in all you should be able to get a nice middle-spec machine for 2 grand. Regards, Glenn