The partnership evidence is always a nightmare! I know a number of people who got asked for more things (my husband and I were for our Skilled Migrant PR application...) - your CO will contact you if you need to give anything else - if so, then you could get statements from friends and family saying that you are in a bona fide relationship - but s/he will let you know what they are after (our CO was very specific on the things that he was looking for).
I'm not sure which branch you've submitted to, but the Wellington one has this info on it:
which indicates that you should hear within a year.
(There is a full list of branches here: http://www.immigration.govt.nz/migrant/general/aboutnzis/contactus/