Take it to the principial.
Don't be obnoxious and think you are right about, admit that you are wrong and shouldn't have spoke out in class, but that you were protecting your heritage. You didn't throw a punch, that you tried to debate it on a civil level..
YOU ARE IN THE WRONG. Accept that. You shouldn't have carried on with her. The school system sucks, BUT you have the right to take it higher. If the principal doesn't want to hear anything of it, take it higher. At least you haven't screwed your relationship with them.
(My suggestion is, that you were disrupting class, but that was because you were insulted with her having no right in the situation.)
Oh yeah, and after getting this resolved into some dentions.. Switch out of that class asap, again take it up with the person who finally helps you.. Say that last year, you had a less then stellar teacher but you were still competent in class.. Ask if you can take test of your aptitude.
EDIT: Also, you are not looking to punish her but rather have the suspension taken off record.