Searched and couldn't find many specifics, was hoping you guys could enlighten me.

I have the standard Comm SEL/MEL IR, CL65 type, blah, blah... What would it take financially to add on a commercial helicopter rating and how long generally could I expect to be training? (I know it will vary depending on how much I fly). My theoretical goal would be to switch from airline flying to AirCare (EMS) type work after countless hours of instructing, flying the pipeline, etc to get req experience. Any other input and words of wisdom are greatly appreciated.