The woman became so concerned she took her children - aged 5 and 2 - to the car parked in the driveway.
Officer took the keys from the ignition and threw them aside.
As the victim got out to retrieve them, he pushed her to the ground, straddled her and grabbed her around the neck.
The defendant's cousin tried to intervene but was unable to stem the violence.
Officer lifted the woman's head and dropped it on to the gravel driveway at least five times, the court heard.
One of the children saw him then punch their mother in the face, and began screaming.
Officer went inside the house and the victim, who wanted to get her handbag, followed.
However, when she found it, Officer was blocking her exit.
He punched her again, causing her to fall to the ground.
With blood streaming from her nose, the victim fled outside. Officer followed.
While the woman was on her hands and knees looking for the car keys, he pounced again.
The defendant pushed her to the ground from behind and again held her by the neck.
''The victim couldn't breathe and was choking on the blood coming from her nose as a result of the punch,'' a police summary said.
Eventually, the third party was able to drag Officer away and the woman left with her children.
The court heard she suffered serious bruising to her face and arms and had trouble swallowing or speaking in the days after the incident.
In a statement, she said she was stunned to think the ordeal had started because of misplaced tobacco.
Defence counsel Deborah Henderson said her client was motivated to change his ways and Judge Michael Crosbie acknowledged he had undertaken several courses while on remand.
The violence meted out, however, was ''shocking'', he said.