2001 Subaru Forester fuel

Engine Performance problem
2001 Subaru Forester 4 cyl All Wheel Drive Manual

Hi there, when im driving my car it runs great everything good except when Im coming home from town and I have a long hill to come up, it sounds and feels like it's not getting enough fuel. Sputtering and losing power. I just changed the fuel filter, I just put in one I had here, inline. Not like the little bllack pot one that was in it when I bought the car. Did notice that the fuel is dirty, the replaced fuel filter lasted one drive. Any Ideas? Would be great. Thanks. Sue