Sounds like you need a new metal lining....? What did the CRG say?

And all of us on the internet with our psychic visions of your particular chimney struggle mightily to see what your in person expert saw himself.

http://www.oldhouseonline.com/making-sense-of-chimney-liners/

How about a Bio-Ethanol burner insert for your fireplace. No Chimney is needed, you still get a real flame, plus the heat you are wanting. This way no repairs would be needed to your existing one. Check out our options at http://www.ethanolfireplacepros.com/burners.html

Well what did the chimney repair guy suggest? If you don't like his suggestions, and even if you do, get a second or third opinion.

You can insert a wood stove with its own chimney or a gas fireplace. No need for structural repair and similar experience. The gas and wood stove actually heat better than an old fashioned fireplace.