1996 Ford Taurus Heater core repair advice

My engine pours out coollant/water and I had problem diagnosed as the heater core by a general automotive repair shop est. ($500-$800). I read about the bypass option. In either case. My question is where should I take it to be fixed at the BEST price?
1. A general auto repair shop.( Not the dealership. $900+ Yiikes!)
2. A radiator shop
3. Heating & cooling specialist shop

Thanks