Starting a restoration - Rusted Passenger side A-Pillar

Hi guys,
 I'm in the process of starting my very first restoration - a 1967 fastback - and the condition of most of the 'pile' (Can't really call it a car yet lol) has me excited.  The guy I bought it from had already torn the car down and performed the majority of the metal work needed on it.  He replaced the floor pan, the dashboard, the cowl, firewall, inner fender aprons, core support, quarter skins, leaf springs & shackles, and tailpanel along with buying a new differential.  

The only area (metal wise) that has me worried is the passenger side A-Pillar.  There is a spot on the bottom corner of the upper portion of the pillar (just above the upper door hinge where the bottom of the window would meet it) that is nearly completely rusted through.  I don't know much about how A-pillars are constructed, but upon examining it, it seems to me that the pillar is made of several pieces of metal that wrap around one another(is this a correct assumption of its construction?)  If this is accurate, then the "outer layer" of wrapping is nearly completely rusted through. The other pieces that are beneath it do not look quite so bad, but I don't necessarily trust my assessment.  I have a couple of friends that are pretty solid at doing body work, and I'm going to talk to them when I get a chance but figured I'd ask about repairs in here.  How in the world do you go about repairing a rusted up A-Pillar?