Yes, Miros has safety deposit boxes in reception which can be hired for a reasonable charge. As for taking Euros, last time we went (3 years) there was not a lot of differance in the exchange rate whether bought here or there. There are several places in Tingaki where you can buy Euros.

 

Miros Studios are a very nice place to stay, we have stayed there 3 times already and are going back in a couple of weeks. I don't think you will be dissapointed.