help converting to a power steering gearbox

I have a 1970 Plymouth duster and i had to jimmy rig my steering setup because the person i bought it from gave us the wrong coupling and now I'm thinking of just adding a power steering gearbox (its manual right now). I am looking for a kit with the coupling, the gearbox and the pump. If someone can help me either find a website that has what I'm looking for of maybe if you have the kit that i am looking for then i am happy to negotiate.
thanks,

Ben