Welcome to the site.
I doubt if any one here will venture a guess on cost, evan if you get contractors out to look at it, it may be hard to get firm prices,before digging into problem areas.
How old is the house, and have you had a look at the foundation and the wood near it?
How old is the roof and do you have any leaks now? Is the chimney still being used?
Have you inspected the wood around the windows, inside and out?
As you might be able to tell I would inspect everything from ground up so that any repairs don't just hide problems that would show up next year or soon after.