Heartland had previously announced it will stop ambulance service at the end of June.
Voters approved a half-cent sales tax increase to fund the new county-run ambulance district.
Commissioners say they are meeting with Heartland officials every other week.
They're still in negotiations about contracts and licenses, and those talks could continue for a few more months.
The county is trying to make the transition as smooth as possible.
"The first year is going to be pretty tight and pretty critical," Presiding Commissioner RT Turner said. "So as far as having money to go out and actually buy equipment and take employees over, that'll probably be in the second year when we look at those kinds of things."
Commissioners say they won't begin to collect revenue from the ambulance tax until June.
In a full year that tax is expected to bring in around $2.8 million.