If you haven't yet accepted, you should definitely express that you were looking for something a bit higher. They've all but told you TO ask for something higher when they said "Is this what you were hoping for?" There's a great chapter in Sheryl Sandburg's book Lean In that basically says that one of major reasons that men make more than women is because men negotiate harder (or more than not at all, as is often the case) for higher starting salaries. Over time, that turns into a bigger and bigger disparity between men and women. When you bring it up again, you should definitely have some reasons for why you deserve a bigger salary (it's more commensurate with your skills and experience, etc). You don't need to belabor it. Most hiring managers have a range that they can safely/easily give new hires. Why shouldn't you get it?