What a difference a day makes.

On Tuesday, 8-year-old Kaitlyn Bradfield was in the intensive-care unit at St. Christopher's Hospital for Children with a tube down her throat, while doctors tried to determine just how badly she had been injured by a hit-and-run driver earlier in the day.

Yesterday, Kaitlyn was up and chatting on the phone to her enormously relieved relatives.

"She called and talked to everybody," said Dorothea Ball, the girl's aunt. "She asked her mommy to bring her dolly to the hospital.

"She seems upbeat," Ball added. "It's a world of difference, for sure."

Police said that Kaitlyn and her twin sister, Eryca, were struck by a gray Lincoln Towncar at Colgate Street and Cheltenham Avenue about 3:30 p.m. Tuesday.

Eryca suffered bumps and bruises. Kaitlyn suffered a worse fate - the car actually rolled over her abdomen, leaving tire marks on her body. She was initially admitted to St. Christopher's in critical condition.

She has since been upgraded to good condition, and the worst of her injuries appear to be a broken ankle and broken arm, Ball said last night.

Meanwhile, the hunt for the motorist who mowed down the girls took an encouraging turn yesterday.

Police identified Shawn Timbers, 22, of Alcott Street near Frontenac, in Northeast Philadelphia, as a "person of interest" in the case.

Timbers is believed to be a relative of the owner of the Lincoln, an investigator said.

According to court records, Timbers has been arrested five times in the last three years, for offenses that include drug possession and unauthorized use of a motor vehicle. None of the charges resulted in a conviction.

Detectives found the car on Cheltenham Avenue near Summerdale Avenue a few hours after the accident. Their investigation was aided, in part, by a handful of residents who witnessed the accident, then chased after the car and jotted down the license-plate number.

Ball said that family members believe that an angel was watching over Kaitlyn and Eryca, who were hit as they walked to a corner store.

Eryca, who was treated and released from St. Christopher's a few hours after the accident, has pined to be with her sister.

The two girls, Ball noted, are inseparable. "Eryca told her mom she wants to be in the hospital, with Kaitlyn," she said. "They're very, very close."

Anyone with information on Timbers' whereabouts can contact police at 215-685-3180.