"We are definite for 2017 and we've got an agreement for 2018 and 2019, but we've got to do some work on funding.
"It's a good result and it's nice to lock it in for 2017, but we've still got to put our sales hat on and convince the government that we are worthy of some more.
"You can't sell enough tickets to pay for a V8 Supercar event, it's just not physically possible."
Supercars is expected to formally announce its calendar for next year after this week's round at Sandown, which marks the start of the series' endurance season.
The result for Winton means Victoria looks set to keep its full quota of events on the calendar for next year with Supercars also close to finalising a new deal at Sandown.
Warburton said Supercars was eager to retain its presence in country Victoria.
"This is a great win for fans in regional Victoria who enjoy coming to this iconic venue," Warburton said.
"We look forward to returning next year and ensuring Winton can receive the necessary support for the event for 2018 and beyond."
Winton has hosted a Supercars event every year except two since 1985 and provides a significant boost to the region's economy.
The venue, which recently underwent a $1 million surface upgrade, is also used as the test track for all the Victorian-based Supercars teams.
"For testing, the Supercars teams need a circuit that has a variety of different corners, through which they can gather data that correlates with other tracks on the calendar, and Winton offers that," Lewis-Williams said.
"The local teams will be relieved they will still be racing at the track where they test."