Aiono's car crossed the road, went through a fence and collided with the two girls, sending them over a fence.
Crown prosecutor Mark Williams said Aiono then tried to drive away but his car was too damaged.
He also tried to run off but passersby stopped him and brought him back to the scene. Aiono blew a breath alcohol reading of 503 micrograms of alcohol per litre of breath. The legal limit is 400.
Judge Charles Blackie said Carmelite was in a coma for 10 days with extensive head injuries.
The court heard an emotional victim impact statement from her mother, Pepelemi.
She described how everything went "black'' when she saw her daughter lying on the ground after the accident.
Pepelemi said doctors told her that even if Carmelite did survive, she would have brain damage.
"Carmelite needs to be turned regularly over and have her diaper changed - it's like having a baby again.''
Pepelemi said she tried to stay strong for her daughter.
She wept as she told the court that her daughter's teacher has said Carmelite's reading age has gone backwards.
"Last year she shows skills as a leader, now she is too scared to do anything.''
Judge Blackie said everyone in the court would have been moved by Pepelemi's words.
He said the two innocent girls had had their lives "decimated'' by Aiono.
"It is not OK, it is totally irresponsible.''
Aiono had earlier pleaded guilty to two charges of driving with excess breath alcohol causing injury, as well as driving while disqualified and failing to stop and check for injuries after being in a crash.
His lawyer Hermann Retzlaff said that in Aiono's native Samoa, people involved in crashes with pedestrians are encouraged to go to the nearest police station instead of stopping because drivers have been killed by grieving family members.
"Those were the instructions to me when I asked him if he was trying to leave [the scene].''
Aiono's wife, Deborah, apologised on behalf of her husband and said she would feel just as angry as the girls' families if someone harmed her children.
She asked everyone to think twice before drinking and driving.
"When you drink and drive, you may injure someone. Not only will you suffer but your whole family will suffer also.''
Judge Blackie took time off Aiono's sentence for his remorse and his early guilty plea.
He disqualified Aiono from driving indefinitely.