My fireplace is losing too much heat up the chimney. Is there a way to delfect it?

You ARE going to lose heat up the chimney. Couple of things you can do to keep SOME of it in the room. Got a set of doors for the fireplace? They need to be open while burning, but can be closed as fire goes out, keep from sucking warm air out of the room. There are heat exchangers that are metal tubes with a fan. Tubes heated by the fire, fan pushes air thru the tubes, out into the room. The "Heatilator" style fireplaces have a heat exchanger built in to the fireplace. The heat exchangers are not cheap, and are still not as efficient as a wood stove.