He heard screaming and ran over to help while his passenger phoned 111.Mr Rowe said the girl had been dragged about 8-10 metres before the car came to a stop.
"I tried to reach her from the driver's side of the car but the vehicle was completely bogged down in the garden. I couldn't feel for the little girl from the driver's side so I ran around to the passenger's side and started digging bark and stuff away to try and free her but she was completely pinned.
"I was calling out to her but she wasn't answering.
"About four or five of us held on to the side of the car and lifted it off the ground and one guy ran around and pulled her out from under the car. Her uncle then grabbed her and cradled her in his lap and I sat in front of them on the footpath, holding the girl's hand and talking to her and trying to reassure her when she kept asking 'am I dead, am dead?"'
He said the girl had grazes on her face and chest and appeared to have a broken tooth.
Mr Rowe said the girl had been wearing a cycle helmet and said he believed this saved her from more serious injuries.
The girl, who had been visiting the carpark with her uncle, his two children and her brother told him that it was her 11th birthday and it was her "worst birthday ever".
Peninsula Panel & Paint's James Hope and his brother Fergus also helped lift the car off the girl.
"They just got it high enough to get the girl out ... They pulled her out, there wasn't any room under there. I don't know how she was still alive."
I don't know how she was still alive.
He said he heard screaming and saw the car - then ran out to help. The girl was under the car for about two or three minutes before they got her out, he said.
A St John Ambulance spokeswoman said they were called to the scene at 10.43am and the girl was rushed to Thames Hospital in a moderate condition.
New World's checkout manager Jamie Portersaid she was first alerted to the incident when a customer ran into the supermarket asking staff to call an ambulance.
"We ran outside and found the girl was on the kerb by then. They had a towel round her and they were comforting her - telling her everything was okay.
"She could move her feet and her toes - but she was a bit cut and bruised."
Ms Porter said the girl's uncle was pretty startled by the incident.
The young driver of the car was also upset, Ms Porter said.
"She was quite shaken up about it all. I heard her saying to her mum 'I'm never driving again.'
"It would have scared the life out of her - it would have done that to the best of us.
"It was plain and simple an accident. She was a learner driver, she had her fully-licensed driver in the passenger seat, she had her 'L' plates up, she was all legal and it was just a very unfortunate event."
Police said the young girl was with her parents at the hospital, and was "looking good," though the incident had been "very scary and traumatic for everyone involved".