Replacing the head gasket would require removing the timing cover, intake manifold, exhaust manifold, removing all the accessories- yeah, it's not something you jump right into.
Your crappy running was likely due to the usual suspects- old plugs, old fuel filter, bad PCV vacuum line, old PCV valve, plug wires, maybe a bad coil- etc.
Now you have a coolant leak from somewhere, and if the car is overheating that will eventually cause a bad head gasket. You should locate and repair the leak first before jumping into a head gasket job.
Once again- was it smoke or was it steam? You smelled coolant, so I'm going to assume it was steam and not smoke. I'd also assume that your car is low on coolant. First off, you should go ahead and change those plug wires/plugs if you have them. If you don't have plugs- no big deal, remove the plugs anyway and inspect the plug deposits. We need to know color and consistency (dry, flaky, wet) of the deposits on the old plugs to verify some of your running problems. You can find plug deposit charts online, or in any auto service manual. Identify and record the deposits, and also note if one cylinder has different deposits than the other, as that is important. Check gap, and install the cleaned plugs. You only have to scrape deposits off the sparking surfaces of the plugs with a knife, but a wire brush is the easiest tool to use for this.
If there is any coolant or water in the spark plug tubes, use a rag or a shop-vac to remove as much as possible. Don't worry if a little gets in the cylinder when you remove the plug.
Before starting the engine, fill the coolant reservoir up with water. You will want to massage the hose going to the radiator, and give enough time for the water to settle. Try to make sure it is as filled as possible. Be careful not to spill any water if you can because more than likely something will start dripping as you fill. Try to find the hole that is causing the drip. The thermostat housing on these engines is known to crack and cause coolant leaks. If you think you've filled the system as much as you can, and still haven't found a leak- put the cap on it and start it. This will circulate the coolant in the engine, and force any air out of the leak. If I'm right, you'll find a leak somewhere- if I had to make a guess, it would be one of the radiator hoses or the thermostat housing itself.
If you find that's it, then I highly suggest replacing both hoses because your car is approaching 10 years of age, and rubber typically lasts about 10 years unless it's coated in grease and dirt. If you find that the thermostat housing is the cause of the leak, then you should replace the thermostat when you do that repair.
Once you get the leak repaired, you should double check to be sure that the engine cooling fans are working properly. These cars have 2 speed fans, and as it ages the resistor which operates the low speed fan can go out. The fan only kicks on at high speed when the coolant temps are close to 220F. This is very close to the temperature that will damage hose integrity. It very well might be that the hose is damaged due to age, and high heat- and this busted hose prevented you from damaging the head gasket. If you have trouble verifying the operation of the fans, then we can work with that after you find the coolant leak.
I'm fairly certain that's what you're going to find from what you described. The reason you had steam/smoke coming out of your exhaust is because the air intake was sucking up steam from under the hood. Steam, as I pointed out earlier, will clean the inside of your combustion chambers like nothing else resulting in thick white smoke as the engine burns up all the carbon in the chambers and exhaust manifold. When a head gasket goes out, you typically don't have steam or smoke on the inside of the engine compartment. Usually the engine will not start, will run horribly if it does start, smoke and steam from the exhaust, and oil will mix with coolant. Another side effect other than oil/coolant mix is loss of compression- the starter will spin the engine freely, very fast, and it will not start, or might merely sputter some.
Check very carefully to see if you merely have a coolant leak as I have guessed, and repair that. Hopefully that is all it is, and we can get to work on your running problems after you have repaired the leak. Oh, and once you do repair the leak, you'll want to fill your car with the proper coolant mix, and while you don't have any coolant in the vehicle (while you're repairing hoses) you should flush the coolant system. When you've checked and located a leak- or not located a leak (cross your fingers that you do) stop back in and we'll make more suggestions. Hopefully those will just be how to flush your engine cooling systems, or how to tell if you need a new thermostat housing.
