The girl had been in the hospital being evaluated for a serious head injury.
The accident happened around 1:00 p.m. Saturday at the restaurant in the 800 block of South College Avenue in Newark.
Police say a minivan maneuvering into a parking spot suddenly accelerated right into the side of the building.
That minivan hit a wall that was shared by the women's restroom. Inside that rest room, a 31-year-old woman was changing her two year old's diapers on the changing table.
The impact sent them flying amid a shower of debris. Both were trapped in the rubble.
Another woman was also in the restroom and ran for her husband to get help.
"He actually had to pull, pry a door back to get to them and render aid to them until rescue personnel could arrive," said Lt. Mark Farrall of Newark Police.
The two-year-old suffered a head injury while her mother suffered a leg injury.
The van was driven by a 17 year old boy.
At this point, police don't know what caused the sudden acceleration into the restaurant. It could have been operator error by an inexperienced driver. But, the police are also checking out the van.
The 17 year old driver and his younger passenger were shaken up, but uninjured.
Police say there was no evidence of drugs or alcohol.
So far no charges have been filed and an investigation is ongoing.