"I was last in the line, and [the attendant] said we had seven minutes and my daughter and son were taking their time getting their tickets," said the woman, who chose not to reveal her age or occupation.
"I was the last, before it tipped over. It was right on the cut-off."
The woman said her family had been living paycheque to paycheque. After getting engaged last year, she and her partner had hoped to buy a ring for Christmas.
"There was an engagement ring that I really liked, but it was $500 - way over our budget.
"I said, 'I'll deal with this $100 ring', and he said, 'No, none of these rings are good enough, you'll have to wait longer for your ring' ... I think I'm going to get a pretty good ring now."
After watching the draw on TV, the couple rechecked their numbers and called some of their extended family together.
"They thought they were in trouble," the woman said. "Everybody was jumping for joy, and crying all at the same time. And then we gathered together and we said a prayer."
Service station manager Mitesh Chaudhari said the win was a reason for all to celebrate.
"It is good for the whole community, the business, the customers. It's a good buzz all round - everyone keeps smiling," he said.
"It is very exciting. Unbelievable. Fifteen million dollars - it's amazing. I couldn't sleep last night thinking about it."
Yesterday, the winners were determined to keep their feet on the ground and work out a plan.
Much of the money will go to help close friends and family, and they want to spend a substantial amount on charitable work in Africa.
The woman said a new home - with a pool table - would replace the cramped two-bedroom flat they share with her son and her sister-in-law and her husband.
The couple had to borrow money to travel to Wellington to claim their prize yesterday.
They had no money for a motel, so they got changed in a service station toilet before walking into the Lotteries Commission building to claim their $15 million.
"We wanted to dress nice when we got here, with tidy clothes, but we needed to get changed somewhere," the woman said.
"Then we came in with big smiles to claim the money ... Everything has just sort of fallen into place."
Liz Koh of financial planning company Moneymax said anyone coming into that amount of money should leave most of it in the bank for six months or a year.
Financial and legal advice should be sought on issues such as ownership, taxation, investments and inheritance.
How they'll spend it
*An engagement ring
*The wedding
*A new home (with pool table)
*Charitable work in Africa
*Helping out close friends and family
