What news did Melba get while she was in Cincinnati in Warriors Don't Cry?

While she is in Cincinnati, Melba gets the news that she has "been assigned to go to Central High with the white people".

Melba is in the midst of a glorious visit to her Great Uncle Clancey's family home in the city with her brother, mother, and grandmother.  Melba has found Cincinnati to be "the promised land".  In contrast to the narrow-minded prejudice with which she had always lived at her home in Little Rock, she has found that in Cincinnati she can walk "with (her) head held high".  There are no Jim Crow laws in the big city; white people are generally friendly, and Melba can use the same facilities and eat at the same restaurants as everyone else without a thought.  Melba has just decided that she is never going to return to Little Rock, and is planning how she is going "to beg and plead with Uncle Clancey to let (her) live with them and finish high school in Cincinnati" when she receives the news.

At school a few years earlier, just after the Supreme Court ruling that separate schools for Negroes and whites were illegal, Melba had, without her parents' knowledge, signed a paper expressing her desire to attend Central High School, which was all-white.  In the intervening time, as lawsuits and petitions kept postponing the date for integration to begin, Melba had decided that the great change was not going to happen anytime soon, and had ceased hoping to be a part of it.  That day in mid-August of 1957, while the family is watching a news announcer on television talking about how seventeen children from the Little Rock community have been selected to enter Central High in the fall, Melba's father calls and says he has just been notified that Melba is to be among the seventeen.

As Melba tries to fend off her family's "harsh inquisition" about her poorly thought-out decision, she realizes that, for the moment, she "no longer care(s) the least bit about Little Rock; (she) just (wants) to live right there in Cincinnati".  She is, at this point, however, committed to an extent, and she returns home with her family "to begin living a life (she) had never imagined in (her) wildest dreams" (Chapter 3).