there are bank web sites with up to date exchange rates. u pay the US cost in equivalent NZ dollars. make sure u check the conversion rate BEFORE u order and so on and so forth i know u know what ur doing.
the web sites have converters that do the work for you. here's mine.
http://www.bnz.co.nz/Personal_Solutions/1,1184,1-1-122-815,FF.html