It is not permissible to work in interest based banks. It is strictly forbidden. It was transmitted by Muslim from the authority of Jabir that the Messenger of Allah (peace be upon him) said: Allah courses one who accepted usury, the one who paid it, the one who recorded it, and the two witnesses to it, saying they are all alike.
The basic principle is that she looks for a job that is permissible in Shariah if she needs a job. Otherwise, many house chores await her in her marital home.