Need some advice on painting

I'm really new to this, so I need some help. I am going to be getting a set of armor in the near future... but I've never worked with an airbrush before. I was wondering what kind of airbrush I should get, and what paint I should use...

I will be using a MR helmet (ESB style), so I will be painting just the armor pieces. so, I was also wondering... is the helmet color the same as the armor color?

airbrushes are really personal preference, obviously the more expensive they are usually the better they will be, but for instance the top of the line airbrush from one company will be the equivalent of the lowest of the line of another company. If I had a couple hundred at the moment I'd invest in an iwata. I've had testors and paasche but wasn't really pleased with either. For beginning I would suggest a single action, internal mix with a gravity feed paint cup.