"My nine-month-old grandson would have been in the car with us, had it not been for a change of plans," she told News24.
CCTV footage has gone viral on social media and five suspects have since been arrested.
Police investigating the incident found that the group of armed men had followed her home from a local mall.
When the woman was indicating to enter her driveway, the hijackers made the move.
"I was ready to open the boot to my car, when I saw the white car behind us," she told News24.
"I told my daughter, 'don't get out, just close your door'. When I saw the men approaching us, and I saw their guns, I told her, 'here comes trouble'."
The woman pressed a panic button and waited for help, all the while trying to keep her teenage daughter calm.
"I kept talking to her and I even turned the radio up, so she wouldn't hear the hammering of the gun against the window or their shouting.
"Those seconds felt like an eternity."
Ramming her car into the men was not part of the plan but her daughter became very upset and she instinctively made the move.
"Before I realised it, the car was in reverse," she recalled.
She then proceeded to ram the hijackers' car multiple times.
The men ran down the street and the family was rescued to safety.
Mother and daughter are currently receiving trauma counselling.
