^ Yeah take a break from her for a few days. Don't call her or email her.
Leave your friend alone with her own anger for a while.....and maybe she'll reflect over her attitude and the overall situation.
Talking to her about it is not helping. Maybe showing her will be more effective. Sometime in the future....i suggest you invite this friend and other friends (from a variety of races) to lunch/dinner. And just expose your friend to people of races she's prejudiced against. ** Don't **make it obvious that you're trying to educate her, keep it natural. A few exposures might help change her mind.
And if that doesn't work either, then just change the subject when she makes such offensive comments. Your silence and changing of subject might be strong enough a message that you don't approve of such an attitude. It seems you still want to keep her as a friend, so focus on the positive aspects in your friendship. Because it's tough to change people unless they realize it on their own.