He said he initially he thought she just having a nap but after getting half way across the road he decided to go back and check she was okay.
It turned out Ellison was type 1 diabetic who suffered from hypoglycaemia unawareness - a complication of diabetes in which the person becomes unaware of a deep drop in blood sugar.
"I opened car door and it was like opening an oven, her clothes were wet and she was unconscious, unable to move or talk," Donovan told the Herald.
He rushed to the nearest shop to call an ambulance and then assisted Ellison out of the car and into the shade.
"I saw she was wearing a diabetic badge so I thought she might have some medicine in her bag. I saw she had some jelly beans so I gave her some of those which seemed to help," Donovan said.
He said as Ellison was getting carried to the ambulance she stretched out her arm and mouthed the words "thank you".
"That was the last I saw of her," Donovan said.
He says he's no hero but Ellison thinks otherwise.
"I don't think I'd still be here if it weren't for that man and I really would like to find him," Ellison told the Herald last week.
"I think someone up there was looking after me because I hate to think what might have happened if I had driven.
"I just can't get over how lucky I was ... I really would like to meet and thank him," she said.
Tomorrow, a week after the close-call incident, her wish will come true.
The Herald will be meeting the pair as they reunite for the first time.
