A man crawled up the fire escape of the 47-year-old woman's Mulberry Street apartment about 3:30 a.m. and broke in through her window, police said.
He then showed a knife and sexually assaulted the woman, police said.
The suspect did not harm the child, according to police.
The man was last seen wearing a black leather jacket, white T-shirt and knit cap, police said.
Video of the suspect walking down the street was released Tuesday morning.