Once the woman cleared the child's airway and placed her in the recovery position, the girl resumed breathing.
The girl was treated at the scene by St John paramedics for more than an hour before she was airlifted to Auckland, still in a critical condition.
Two Northland Electricity Rescue Helicopters landed at the nearby Russell Sports Ground, the other taking the driver of the Lancer and the injured girl's brother to Whangarei Hospital.
The man had broken his legs and had to be cut from the wreckage by volunteers from the Russell Fire Brigade.
The boy appeared to be uninjured but was taken to hospital as a precaution.
The driver of the ute, a Russell man aged in his 50s, suffered moderate injuries and was taken to hospital by ambulance.
Police were yesterday not commenting on the cause of the crash, saying they would wait for the Whangarei-based Serious Crash Unit to complete its investigation.
A witness and the driver gave conflicting accounts as to whether the children were wearing seatbelts at the time of the crash. That is also being investigated.
Two near-empty bottles of spirits, one brandy and one kirsch, could be seen in the front passenger seat of the Lancer.
Sergeant Peter Masters, of Paihia police, praised the Tutukaka woman for her actions in helping the badly injured girl.
He also thanked the volunteer firefighters and ambulance officers who freed and treated the injured.
The crash closed the back road between Russell and Whangarei for several hours.