Post: P.O.Box 34-762, Birkenhead, Auckland City
Phone: +64 021 532 768
NOTE: I don’t sell Begonias.
However, here are two options.
1) I can recommend the Auckland Begonia Circle firstname.lastname@example.org They should be able to point you in the right direction!
2) Order through eBay Australia, some have free shipping to New Zealand you just need to shop around.