Can I marry an atheist woman with our parents' consent? What if she's pregnant?

If I am in a relationship with an atheist woman, then what should I do, leave her or marry her? If I tell her I can't marry her because she is an atheist, she might lie about her beliefs. If she is pregnant (less then 2 months) and she decides to keep the baby then what should my decision be based to Islam? If both her and my parents consent to this marriage, is it ok to marry her?