sounds like you got some oil in your coolant... means you have a blown head gasket... compression test the motor (if you cant tow it to a place that can) that will confirm if it is or not... Your coolant is overflowing because your head gasket is leaking forcing air into your cooling system, and pressurizing it. And now it has probably finally blown and now you have oil in your coolant. Check underneath your oil filler cap, see if it has a milky substance on it, and look inside, milky? If you said yes then you do have a blown head gasket. Don't drive it, fix it.