"Her feet were bleeding apparently. Then they called the ambulance and called the police."
The child was taken to Tweed Heads Hospital for bruises and cuts and was being cared for by family members.
She is not believed to be in a life-threatening condition, but a NSW Ambulance spokesman told Daily Mail Australia that she "will have been submerged for some time".
Witnesses revealed the girl's father dove into the freezing river along with several others in a bid to save his family, but they were unable to find the car in the murky water.
"The husband came down, and dad and two other boys just jumped into the water and couldn't dive deep enough," witness Sophie Grinham told television's Seven Network.
Another witness, Thomas Grinham, also saw the young girl reporting her family members were swept away by floodwaters.
"She was screaming [that] her mum... sister and... brother had gone into the river in the car" he told the Seven Network yesterday.A retired highway patrol officer revealed he tried to save the occupants of the sinking car, but couldn't reach it.
Matt Grinham dived into the freezing river with three other men immediately after seeing the crash while cleaning up flood damage at a family member's house.
They followed the bubbles in the water as the submerged car continued downstream - but were unable to reach it.
"We were going down feet first trying to work out where the car was," he told the Gold Coast Bulletin.
"Then we tried diving a couple of times but the water was so brown and cold, the flood run off is freezing down there.
"The car was completely submerged when we got there."
Tributes have been flowing for Stephanie King and her two children after the horrific accident.
One friend wrote on social media, "It makes me sick knowing a beautiful family is still in the water, such a precious loss to all that knew you, I know I will miss you terribly".
A woman who said she was Ms King's best friend was too distraught to speak about the mother-of-three.
Ms King's Facebook says she worked as an assistant in nursing at Opal Aged Care in Tweed Heads, previously working at the Tweed Heads Bowls Club.
It says she is originally from New Zealand.
One neighbour, Steven Moller said, he would often say hi to Ms King outside her home and his heart went out to the family.
"They were a perfectly normal family, I would see her loading her kids into the car," he said.
Police divers from Sydney arrived at the crash scene just after 10am in a helicopter to begin the retrieval operation.
The divers will search for the bodies, believed to be entombed in the car after it was swept into a raging river.
Tweed Byron LAC Chief Inspector Mick Dempsey said the car had been located using sonar equipment, about five metres from the northern bank of the river.
NSW Police Assistant Commissioner Jeff Loy said the tragedy would have a huge effect on the family and the Tweed community.
"It's the latest tragedy in what's been a devastating few days for flood-hit northern NSW residents," he said.