Hi, welcome to the forum
When you say you're at a loss as to which company to use, do you mean a migration consultant? Using a company to get to NZ is not required, and most people are able to get through the process themselves, or with the help of forums like these. Only use a migration agent if you feel you simply can't approach the application without the professional support, in which case take a look around this forum for discussions on reliable agents to use - there's been a lot of discussions!
Have you enquired about permission to take your children abroad? If you don't get permission from the childrens father, you may need to approach a court to get the permission. Several of our members have experienced this, so you should get some great advice on this matter.
Your husband is in great demand at the moment, so at least you shouldnt have a problem gaining residency and getting a job!
Hope that helps