Totally depends on how you have to tie into the roof: hip, truss, scissor jointing.... all different costs. you're quality of finishes will also determine your costs and how much you do yourself or sub out.
I'd say anywhere between $8,500 to $15,000 to do the job. (lower end, doing a lot of the work yourself). Definately check out www.wholesalehomeproducts.net down at 400 davidson st. They are a surplus builder outlet and have anything from hardwoods, to windows, to trim, siding, to roofing shingles at almost half the price of Home Depot. They carry many of the same brands as well.