"I panicked because I thought it might have been a pet or a baby trapped inside," Donovan told the Herald.
Instead, it turned out to be 69-year-old Ellison who had been unconscious in her sweltering car for more than three hours.
At first, Donovan thought she was just resting her eyes and was half way across the road when he decided to go back.
"Just to double check she was okay," he said.
When he opened the car door "it was like an oven". Ellison's clothes were wet and she wasn't responding.
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.
As Ellison was carried to the ambulance in a stretcher, she reached out her arm and mouthed the words "thank you".
Until today, that was the last time he saw the stranger he'd saved.
"I was worried she didn't make it," Donovan said.
Seeing her looking fit and health today, Donovan said was a huge relief.
It turned out Ellison was severely dehydrated after preparing for a medical procedure.
Doctors told Ellison that if she had been left in her car for another hour there was a good chance she wouldn't have survived.
"The doctor at the hospital said it was basically like leaving a baby or a pet in the car during that heat and she began to cook," her daughter-in-law Allison Holden said.
"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 said earlier.
For Donovan, his bad day dealing with banking issues became the day he saved a woman's life.
"I don't like to think of myself as a hero but in some ways I guess I am."
He said it was a reminder to keep an eye out for people who may need help and don't hesitate to check if you're unsure.
