Ford Repair: Anti freeze leak? 2000 Ford Taurus, ford taurus, head gaskets

Question
Hello,

My 2000 Ford Taurus, engine E-u 6-c 3.0l, has recently started leaking. I noticed this when the cooling gauge would go all the way to high when I was driving, and the vents would blow cold air when they were supposed to blow heat. When I arrived home a lot of the liquid was leaking underneath the car. When I looked underneath the hood, the antifreeze tank was half empty, but I had filled it with antifreeze a couple weeks ago. I intend on dropping the car off at my automechanic's garage but in the meantime I filled the tank with cold water. How much does this usually cost to fix depending on the severity of the problem?

Answer
that is to broad hopefully you have a water pump or hose leaking-when cooling system is low you will have hot and cold air

other things are timing cover gasket
radiator
heater core
head gaskets
freeze plug/s
any hose
intake gaskets

range 35 dollars for something simple to 1200.00 for major repair.