That's what I have and I've done a lot of work on mine. I should be able to help spare you much of my pain.
Ok that sounds like a heater core water line. The bad news is that the vehicle is built around the heater core, if you follow me. Same thing for the cigarette lighter if you have one.
I would start by referencing your new, best friend: YouTube repair videos!
Go to Google and perform a search for "2008 Sportage 2.0l replace heater core".
You'll find several explanatory videos.
You should open a "KIA" folder somewhere and begin saving your videos for present and future reference.
Post back anytime.