As regards the question, Sheikh Muhammad Salih Al-Munajjid, a prominent Saudi scholar, stated,
The scholars differed concerning the ruling on Muslim woman can taking off their hijab in front of non-Muslim women. However, the more correct view is that it is permissible for a Muslim woman to appear (without hijab) in front of a non-Muslim woman, unless she fears that the woman may describe her to her husband or to any other stranger (non-mahram man). In that case she has to keep her hijab on in front of that woman. There is no difference between a non-Muslim woman and a corrupt Muslim woman in this case.
Sheikh `Abd Al-‘Aziz ibn Baz (may Allaah have mercy on him) said:
“It is not obligatory to wear hijab in front of them – non-Muslim women – because they are like all other women according to the more correct of the two scholarly views.”
It is noted that what the Muslim woman can show in front of a non-Muslim woman is the same as what she can show in front of her mahrams, i.e., the places of adornment or the places of wudu’.
You do not have to switch rooms unless you fear that living with her in a single room can affect your commitment to Islam.
If there is no expected harm from her living with you, it is our advice to you to take the advantage of her being close to you and call her to Islam through your good manners and perfect explanation of the teachings of Islam.
May Allah guide all of us to what pleases Him!