Re-wiring an old house?
I think you need to find someone to help. Hopefully you can afford a licensed electrical contractor. Remember dude, electrical work can be done by a lot of people but, it's tricky and the results can burn your home down (or worse...you know).
Sounds to me like your into a pretty big project. Hell, in my opinion it's probably worth messing up a few more walls and re-wire the whole house!
If you give the electrician the freedom to do what's easiest and not worry about plaster, geeezz... piece of cake!