my 94 cavalier is leaking anitfreeze?

hi i have a 94 cavalier 2.2, its leaking antifreeze at this little elbow looking thing, right infront of the passenger side firewall,(dirrectly below another line i think goes to the heater core? i dont know) not connected to the engine, but its still taking all the antifreeze out of the reserve tank, what the heck is gonig on? i know thats a little bit confusing but somoene might understtand. only other thing i noticed is my radiator is still full to the top...?