Rosita Espinosa is Abraham Ford's girlfriend, and one of the survivors Rick and his group met up with shortly after the fall of the prison in the comics.
She's expected to make her first appearance on AMC's The Walking Dead soon, with some sites reporting that her boyfriend Abraham has been confirmed to appear in the next couple of weeks.
Rosita in the comics is one of the longest-surviving members of the group, having first appeared in The Walking Dead #53 alongside Abraham Ford and Eugene Porter but not yet having died. This means that, in spite of having a fairly small role for much of that time, she's actually outlasted major characters like Lori Grimes and Tyreese in the comics.
It seems likely that they have similar designs on her for the TV series, since she's being played by one of the more recognizable cast members they've brought on board since the series launched in Christian Serratos, who is best known for her role in The Twilight Saga.
While Rosita has a lot of strength in terms of her ability to cope with the post-apocalyptic world, she's not likely to change the narrative among many critics that The Walking Dead is a little light on female role models; she's been employed throughout her character history mostly as a romantic foil for Abraham. That's a criticism that's unique to the TV series, though, since in the comics Andrea is one of the best female characters in current publication. If Rosita could take on some of her personality and story significance, Rosita could be a real boon to the cast dynamic.