leave the shock collar mushroom, you have got a far better chance with the dog being that bit more closer, what i would do if i was you, would be silent and let the dog go, when she is at the distance, call her in....fuss,fuss & more fuss. Back out again, same again, repitition is the key, its much harder when you are 100m and 200m away, the dog is used to being a huge distance. away.
GOOD LUCK to the both of you,