2000 Ford Taurus Blown Head Gasket?

I have a check engine light that comes on and it is a cylinder 4 misfire. I replace that plug, and 4 days go by and the light goes off and then comes back on. The plug is always rusty looking on the tip when I remove them. I am always overheating in traffic in 95 degree weather. I replaced the thermostat one day and there was no water in the hose. Water pump is making noise. I have to refill the reservoir every 2-3 days because it empties. I have a coolant leak that appears to be coming from the timing cover gasket. Perhaps the head gasket on that side, hell I cant really tell, too tight to see clearly. In the morning when I start the car, it idles VERY rough for roughly 20 seconds and steam / smoke is coming from the pipe. Any idea as to what this may be? This is a 3.0 Vulcan motor (the flex fuel model)