However this would mean we have to relocate and the DH and I are driving 30 mins or so to work while DD also commutes and the younger DS will have to change schools!
I see your dilemma, but isn't it too bigger a sacrifice to make for the rest, just for her to go to a school that has better extra-curricular activities. As Herman pointed out, you could possibly join local sports teams and music clubs outside of the school to make up for it.
However, the advantage you have is that it would be lot easier to relocate as you are currently renting. Where do you see the family settling long term i.e. in 7 years time?