Passey, 20, is charged with first-degree felony child abuse resulting in great bodily harm and third-degree felony child abuse.
"We are still evaluating all the information in the case," said Steve Murphy, Passey's attorney.
The preliminary hearing was scheduled for Oct. 20.
Passey, on Aug. 24, drove to the residence at 160 Desert Rose Trail at about 8:30 a.m., and, leaving her children asleep in the car, went inside, according to the police report.
Alexander Passey, 1, was unconscious when the mother and a friend, Daniel Carlisle, discovered the children around noon that day. Hospital officials flew the boy to the University of New Mexico Hospital where he was treated for hyperthermia.
He remains at the hospital in Albuquerque, although hospital officials would not release information about his condition, Sam Giammo, a UNM hospital spokesman said.
His older sister, Taelyr, was taken to San Juan Regional Medical Center following the incident. She was treated for heat effects and heat exhaustion, then released the same day.
Passey told police the children typically nap until about 10 a.m. and she planned on leaving the residence when they woke up. Passey went into the house to visit Carlisle, but fell asleep while watching a movie, according to the police report.
Murphy denied any sexual relationship between Passey and Carlisle.
While the two adults were in the house, the temperature soared to more than 120 degrees inside the car. The outside temperature increased 20 degrees between 8:30 a.m. and noon.