Hi I need some help with my sisters cirrus

it has water leaking under the carpet passenger side, I pulled up the carpet and looked toward the fire wall and turn on the a/c and heat to see if any water was coming from anywhere and i noticed a black object (think could be a heater core) trickling water out for I believe to be one of cooling fins... I have no knowledge really of these cars so i don't know, but i was wonder how to plug this issue PLEASE SOME ONE HELP ME TO GET MY SISTER TO LEAVE ME ALONE and her ofcourse