Re. Search function, “New Zealand” is a listed country, so you can simply select that in the countries drop-down menu.
Re. finding a partner in an area where there are few registered members of ABFheaven?
Pretty challenging.
But consider:
Parts of the ABFheaven site are “visible to logged-in members only” …profiles, member search results, chatroom etc.
Other parts are publicly visible, eg. these forums, personal ads.
So …on the off chance that a New Zealand woman (not a member) browses the site, finds your personal ad but doesn’t want to join this site in order to contact you …well, you might consider including some form of external contact info in your personal ad, an email address maybe.
Be aware that that contact info would be visible to every spambot & scammer on the planet, and so take appropriate precautions.