Seek advices

Here is my situation,

I am US citizen and petitioned my brother's family (his wife and son) to immigrate to USA in year 2003. Recently, I received a notice from NVC to confirm address, pay fees, and complete DS 260 on line. My brother had a baby girl two years ago. Original I-130 did not have the new baby girl's name on it. My questions is: where and what step I can add the new baby girl to the process so that the family of four can immigrate to US together? do I have opportunity to add new baby girl in processing filling DS 260? Thanks a lot.