What is the Islamic legal position, and what are the sins incurred by a male student who lives with a foreign female student in shared accommodation, and kissing and touching occurred between them, then he repented, and what should he do to expiate for his sin?

This situation is dangerous, as living with a girl entails an unlawful mixing. What you mentioned about the girl's actions and her boldness towards you is proof of this. It seems you were lenient with her, and if that is the case, repent sincerely to Allah. Look for another dwelling where you can be safe from temptation. If that is not possible, take precautions to prevent falling into temptation and continue searching for another dwelling. You must be firm with this girl and threaten to report her to the responsible authorities. Seek a righteous woman to marry, for marriage is one of the causes of wealth. If you find a way to be safe from temptation, then praise be to Allah. Otherwise, it is not permissible for you to reside in that country, so emigrate from it.