Anyone have any recommendations for a network service/support company for a SME based in Newmarket, Auckland?

Background:

Our company develops and hosts a couple of fairly niche/unique online services (psuedo software-as-a-service websites) to a couple of industries in NZ. 

Currently we share the same office space, server room, general network resources with an "ex-sister" company. They were originally part of our company but were sold as a separate business a few years ago.

At the moment they use our infrastructure (office, server room, routers, switches etc) and they provided basic network/system administration for our company.

They are moving to a new office in the next few months and thus we are looking to hire a company to improve and maintain our Network infrastructure  (as opposed to hiring full time network/sysadmin's directly ourselves).

Work Required:

We have a number of things we want improved and done better than they are currently being done and some hardware upgrades required, such as:

Firewall is due for replacement

Improve current network design and architecture

Re-oragnise and repatch the our racks

Review internet connectivity options (We currently have Telecom and Telstra fibre into the building, I believe vector is available also etc)