"This is Ramere, he was 8. ... This is my baby girl, Mariam. She would have been 7 on the 27th," Dosso said from the church altar as she held the little girl's photo aloft. "I promised her a party and ... she's going to get it."
"Don't let them die in vain," she said, urging congregants to get smoke detectors. "Get it done."
The blaze was brought under control in around a half hour but heavy smoke claimed the lives of the seven victims. Six were found huddled together at the other end of the room; a seventh was found near the door to the outside.
Fire officials have said there were no smoke detectors in the house.
At least 10 members of the extended family were at home watching a movie when the fire broke out in the three-story brick duplex at around 10:45 p.m. Friday in a part of Southwest Philadelphia that is home to many of the city's 15,000 Liberian immigrants.
In addition to Dosso's children Ramere Dosso, 8; Mariam Dosso, 6; and Zyhire Wright-Teah, 1; the other victims were Henry Gbokoloi, 54, and siblings Vivian Teah, 26; Elliott Teah, 23, and Jennifer Teah, 17.
The father of the Teah children told the congregation that he was moved by the outpouring of concern from friends and strangers in the Liberian community and said that "only God knows why" such a tragedy could happen.
"I have only one son left now," said Alfred Teah, who brought his family from battle-torn Liberia to the U.S. in the 1990s. "We try to stand strong. ... This is not an end. This is just the beginning.
Fire marshals have not yet released the cause of the blaze. But survivor Harris Murphy, 54, said it started when a kerosene heater exploded as it was being refilled with fuel.
With his hands wrapped in bandages, Murphy told the standing-room-only church congregation that he urged Gbokoloi to have everyone run through the flames but his friend replied, "the firefighters will come and get us." The victims succumbed to smoke before firefighters could reach them.
"Your kids are in heaven," he told Dosso. She stood and embraced him.
The West African community in the region and around the country mobilized as word of the fire spread, and many vowed to pull together resources to help the survivors bury the dead and get their own lives back.
Showih Kamara, president of the Liberian Association of Pennsylvania, said that an account was being set up at Citizens Bank where donations could be made to help the families.
He also said that the group was organizing social service, financial and programming committees to educate the community about home safety and provide any assistance or information they may need. Such community solidarity "is the usual Liberian spirit," he told the crowd.
"We are a united people," Kamara said. "We have come here with the conviction to lead ... to pick up the pieces ... to solve problems," he said. "Not to criticize, but to support from every angle."
Investigators said the basement had only one exit to the outside and that the interior basement stairs had been removed.
The seven deaths increased the city's fire death tally to 37 in 2008, compared to a total of 47 in 2007, according to the Fire Marshal's office.