I would suggest doing the IT technician path on the A+ IMO. It is the most rounded of the three options and allows you to have credentials in both hands on experience as well as general troubleshooting VIA phone.
With anything in the IT field it is about experience. It seems from my research and job searching that Desktop Support and Help Desk support is the first level of support. After you work in that field for a few years and get training / experience you can move into more of an analyst position which is more focused on how the help desk support job is run, at that point you can go into server support, which kind of mixes hardware support, software support, and the heirarchy of how everything fits together in the server with regards to the office(s) you are supporting. After that you can go into system admin role, which is really the architecure role of a server support or support team.
That is GENERALLY the career path from a help desk position, obviously every company has a different career path and that should definately be one of the first questions you ask before getting into a position (as there would be no movement if there is no career path).
So you are looking at starting around 25 to 35 thousand a year for a held desk job depending on the market and company. Once you get into a system admin position you are looking at 125 thousand or more a year depending on market and experience.