ya, like Jay said, you'd likely get quicker results if you use an ice water bath in your sink. Use a sanitized spoon to stir the wort and put more ice into the bath as needed. I was doing 3.5G boils and it would take me about 20-25 minutes to get down to pitching temperatures using a large bag of ice. The combo of chilled top-off water and an ice bath will get you there much quicker.
Primary: Bell's Two Hearted Clone
Carboy: EdWort's apfelwein
Drinking: Edwort's apfelwein, AHS oatmeal stout and lots of new belgium brewery beers brought back to ohio!