Antifreeze leak

I have a base-model 2004 Ford Focus ZX3 5 speed. No bells or whistles. During the last week my battery light comes on when I first start my car. Then after about 1 or 2 minutes of driving it would go off. Every now and then it will come on for a few seconds then go off again. I also noticed that antifreeze was leaking. (I don't know if the two issues are due to the same problem or two seperate problems) I noticed the leak was coming from the underneath of a plactic piece that went across the top front of the car. The piece is like a hard plastic pipe I guess. It has black rubber hoses connected on both sides of it. I'm guessing it's located above the radiator or possibly part of the radiator? IDK. Also, back to the battery light issue, after I put water in my car last night before I left work ( I have to do that every time before I drive anywhere; and no, I dont put it in when the engine is hot) I started the car, the battery light came on again, but this time didnt go off. After about 10 minutes of driving, and the battery light going off and on periodically, all of a sudden my stereo power went off, then all my lights and the power to my whole car! The car started sputtering, I started praying and crying, then pressed the gas pedal like I was revving the engine, then the power came back! I made it home, but dont want to drive it till I know whats wrong. I cant get stranded in the Florida heat with my kids in the car.
I showed my mechanic the leak a few days ago. He first thought it was the hose connection located on the left side (in front of the overflow tank) so he replaced the metal peice that clamps the hose to that plastic pipe thing. But it didnt stop the leak (I told him that wasnt what was leaking!) Then he finally saw what I saw. The leak was dripping from underneath the plastic pipe thing. While driving I guess the antifreeze was also getting blown around, including by the serpentine belt area.
Anyway, my mechanic doesnt know what that part is. He said it was probably a specialty dealer part. I went to Advanced Auto Parts and had a guy come look at it. He also didnt know what it was. So I have been online for HOURS! I cant find anything that remotely looks like the piece that is leaking! Nothing :-( I wish I could find something on line- like a virtual look under the hood-click on the piece and tell what it is. But no such luck. Please help so I can get my car back on the road!