1988 GCM 3500 7.4L gass

My exhaust manifold gasket needs to be changed on the passenger side. I went to pull off the exhaust manifold and found that the reason it is leaking exhaust so bad (hot exhaust is just being trapped under the hood and everything is hot to the touch) is because one of the exhaust manifold bolts is broken off in the head. What is the easiest way to fix this? Or would it just be better to pay someone to fix it for me and if so about how much does that cost? Thanks

Jimbob