What should the questioner do regarding her oath not to re-add her brother's wife to her BlackBerry, given her desire for reconciliation and her brother's wife's apology, and is her oath to sever ties, made in a moment of anger, considered one that necessitates breaking the oath and offering expiation?

If you have sworn an oath and you see that something else is better than it, then you must do that which is better and expiate for your oath. Your communication with your brother's wife is better than severing ties with her. Therefore, communicate with her and expiate for your oath. The expiation for an oath is feeding ten poor persons, or clothing them, or freeing a slave. If you cannot find any of these, then it is fasting for three days.