You should be able to find a spring shop that will re arc, add leaves or make new springs from scratch. If you are going to tow a trailer, add more weight on the back or do anything that will effect the ride height be sure to figure that into the program. You dont want to re-spring it then add weight ad have it sagging. Do an overall evaluation of everything before you start spending on it so you know what you are u against money wise.
I'm not telling you your business but you dont want to get into it and it needs more than you figured. Does it run good, drive stop? Lots of risk with an old vehicle. They can sometimes have very low miles yet just about everything rubber is shot, radiator cores lose their bond on the fins, brake lines and gas tanks rust.