It sounds like your fireplace flue is not creating enough of an up draft to carry all the fire residue up the chimney. You may also have a problem with the chimney on the roof. You may be getting downdrafts down the chimney that are carrying the smell into the house. Adding or closing the damper may or may not help. I'm not a fireplace and chimney expert but you should get one. Getting those old fireplaces to draft properly may take a lot of work. Good luck.