The deal, which was reached last week and approved in court Friday, ends the former couple's custody battle, which has lasted nearly two years.
Federline will retain sole custody of Preston, 2, and Jayden, 1, while Spears will continue to have two visits and one overnight per week and get an additional sleepover by the end of the year, People.com said.
"She's thrilled," Spears's lawyer Laura Wasser told People magazine. "To have more time with her kids has been her motivation to get well. In light of her outstanding conservatorship, she couldn't have asked for anything more."
Spears agreed to increase Federline's child support from $15,000 a month to $20,000 a month and pay his legal bills, which total $250,000.
Spears' father, Jamie, was granted conservatorship over his daughter's affairs after she was hospitalized for psychiatric treatment this year.