I don't think she's gone for good. I have a hunch we'll be seeing her again. The storyline with her and the little girls hasn't really wrapped up and Daryl isn't going to be too happy when he finds out. And speaking of Daryl, I loved when he took that guys whiskey and the dude was gonna draw on him and Daryl just got all up in his face and starred him down. Guy was lucky he didn't get beat.
Possible predictions for Carol:
Daryl goes out looking for her and finds her zombified.
Daryl goes out looking for her, finds her in peril, and rescues her.
Carol finds the governor and returns to the prison to let them know where he is.
If she does survive it'll be tough for her to come back to live at the prison. Tyreese is obviously on the warpath and it will cause a lot of conflict among the others as well.