The winner of the Win Your Dream contest will receive a four-bedroom home worth more than £500,000 in Sedgley, Dudley, alongside a Jacuzzi hot tub and Range Rover.
Lydia and Paul Browning, who own the house, are running the competition to raise £166,000 for Ronald McDonald House Charity UK. Promise Dreams is also being aided.
The date has now been set to September 16. Tickets for the competition cost £2.
A competition spokesman said: "As it stands we have only sold three-quarters of the minimum amount of tickets needed to award the house and car.
"After discussion with the charities and the owners, we have decided to extend the closing date - as we are allowed to do - to September 16 in order to get across the finishing line.
"I know most of you will support this decision as you want to win an actual home and help others too. We are so close."
Wolves legend Steve Bull MBE is supporting the competition.
He interviewed the competition's previous winner Jemma Nicklin, from Bilston,who won a Shropshire farmhouse worth more than £500,000 in February, at the Sedgley property this week.
The video was posted on the competition's Facebook page.
Asked by Bully how she felt about winning the home, Jemma said: "It's just surreal, it has not sunk in fully yet."
There is also a £5,000 prize up for grabs for whoever shares the link the most, leading to the highest number of ticket sales.