About twice as much as you expect...

Seriously, that is a question for a local pro. Local labor rates, housing market, and local rules and expectations make a generalized number virtually useless. Check out the pro listings here on Houzz for local architects and ask your friends and colleagues for their recommendations as well. You may be able to get some basic ballpark numbers from a local contractor. Raising a roof is not a minor project so you will need an architect to work with you