Talk to some friends about good general contractors they have used or know of. You're going to need different trades (framers, roofers, painters, etc.) so a GC can manage these sub contractors. I don't know that you'll need an architect on this, unless your local jurisdiction requires stamped drawings to obtain a construction permit. Again, a good GC is going to know if you need to get an architect involved and probably has some contacts.

I would go to an architect. This could look very " remuddled" if not done properly.