Ballpark cost of a 1st floor dormer?

Does anyone know what a rear dormer on the 1st floor would cost? We saw a house with a very small kitchen/DR and would need to dormer out the back to make it bigger. Not huge, but maybe 15 feet into the back yard and I'm guessing 25 feet across. One level only. Any idea on what we're looking at?

Thanks for your help.

this sounds like my house
we have such a small kitchen and dr its ridiculous i dont understand why the builder didnt just add a few more feet seriously....its so annoying