Ford Repair: Engine Overheating , Stall , Water out muffler, little bit of water, temp gauge

Question
I have a 2001 Ford Explorer 2door sport rear wheel drive . When i tried to turn on my car it took longer for it to start. It did , I travelled for 15 miles or so , got off the freeway and my temperature gauge was climbing fast almost to the red area. I pulled over and there was steam coming out of the front area of the radiator , not from the cap or any visible hoses . The steam got the area wet and i know it was coolant because it dripped and it was greenish color . it didnt drip constant like a hole somewhere it was just steam. I let it sit for a couple hours. once it was cooler weather out, i put extra coolant in in it , and drove it back home keeping a close eye on the temp gauge . the temp gauge was ok in the beginning but halfway through the trip , it would climb fast, but would go back low and never reached the red , until i was like 3 miles from home. I tried to turn on the heater to keep hot air out of the motor , but no heat would come out. only regular air . The check engine light came on. I pulled over and let it idle for a couple minutes , and the chk engine light went off and the temperature gauge went back to the middle , where it is at usually. I took the side streets home , and when i pulled into my parking space , tuned off the engine. The next day , during daylight , i decided to turn on the car , and see if i can see where it is leaking from. My friend was helping me too. i turned on the car , it idles for about three minutes no problem, then the car just turned itself off . . I tried to start it up. It took a couple turns of the key . the first two attempts didnt start the car. The last attempt did the Explorer on . Just when i noticed it was feeling different , when idling , it felt like it was misfiring or something , it just sounded a little tiny bit different , my friend told me to cut the engine off , he noticed a little bit of water coming out the exhaust pipe  . He said he couldnt tell if it was normal condensation , or something wrong. He checked my oil and said it didnt look like there was coolant in it . He said to take it to a mechanic . . I am broke as hell right now , and ive seen these ads for broken head gasket additives that i can put in my radiator , drive it around for 500 miles then flush out the cooling system and replace it with normal anti freeze and voila! gasket fixed , but it sounds too good to be true . the bottle is like 5 dollars. kn makes it.  Would you reccommend trying that ? or is this some kind of classic problem where you know exactly what it is and no can of cheap stuff will help me ... ?? Please help ... Thank you for your time , it is much appreciated !

Answer
Mechanic in a can will let you down 9 times out of ten, and many of those products cause more problems than they might solve. This vehicle needs to be checked out by a qualified technician before the engine has any more damage, or you spend any money on it for gimmicks or supposed quick fixes.