Relations are important. Cannot cut it so easily. Try to use reason with her. There is something important unsaid in your post. We cannot really understand the whole picture without it.
In your place I would keep her away from any kids I had regardless of color. She's either going to treat them horribly or teach them to treat others horribly.
@NinaCherry Well, a lot is confusing. Hating blacks yet getting pregnant with one is confusing.
If she likes you, why would she hate your children? That’s confusing.
If you’re biracial, your children are guaranteed to be as well no matter what race you marry. Hasn’t she figured out that yet and that she’s the cause? Again confusing.
I would tell her first that her words are not appropriate or welcome, I always try in life with people then they can not turn around and say it was me. That just me