I would be tempted to let this one incident go without saying anything but to avoid her, if possible, in the future. And maybe be prepared to call her out with a "Hey, did I do something to upset you? You seem really angry with me." Maybe say it privately once, and then loudly in front of a group if she keeps up the nasty comments.
It almost sounds to me like she was angry about something else and took it out on you. Maybe she didn't want to go but felt pressured to give you a ride when you asked? Why did those other two girls leave? That kind of makes me think she had some kind of other issue going on and she took it out on you. I'm sorry the conference ended on such a sour note