One on one she gives everything she has but in team practice/game situations she falls off a bit.
Another route to take - what about explaining that the second half of your team NEEDS her to be a leader - to show them how to play, what the expectation is and hold them accountable. And you need her at practices and games to show the same effort in one-on-one, as that will elevate the play of the second half of the team.
Now, this is contingent on a lot of variables, but it could be an angle you take when you talk to her if you think it may push her.
Ultimately, though, if you want more out of her you're going to need to find a better team.