Car is leaking coolant and cannot find a hole anywhere?

What is your question?

Recently I started to have coolant leaking from the reservoir and lately I have been putting coolant in it every other week. The temperature goes up and down, when you open the hood, you can smell coolant. I really am clueless as to how the coolant is leaking. Today my husband said the car has cut off on him numerous times. please help me with my darn Buick century!!!!!