First of all, your question needs a correction. A transvestite is a cross dresser. A man that dresses as a woman or a woman that dresses as a man. I think the word you are looking for is transgender. A transgender person is someone who was assigned a gender at birth (example: male) and they do not identify with that gender. They may or may not decide to transition to female.
To answer the question of what prison she should be sent to, I think legally, with the way things are today, she would be sent to solitary confinement. If she has had all the surgeries, they may opt to send her to a women's prison.