I wrote out a whole statement only to accidently press a key that closed the whole menu... bah
anyways...
Racism is not a crime.
Stalking and threatening is. I would report this to the local police dept. and if they are unwilling to enforce the law i would get a restraining order against her. That will look bad on her record and may detour her.
On the other hand this girl is probably singling you out because she knows you are scared. This fear empowers her. It makes her feel right and confirms her belief. This restraining order will only confirm that she has won and has you shaking in your boots. She may stop in fear of the law but in that case her mission is still accomplished. The law may not detour her though... it may excite her even more, and persuade her to continue. Either way you will play the roll of the victim and walk away humble and ashamed and remember this for the rest of your life. "to say yes to an instance, is to say yes to an eternity." This may make you easy to walk on in the future.
Good thing about the restraining order is if she is in your presence you can defend yourself and the law will be on your side. But it may be that order that brings on this attack. Makes you look scared. You will lose this fight because you took the victims way out and wont have the will to fight.
Another option is to wait until she is publicly stalking you and walk up to her and ask her what she is doing? not aggressively, assertive is the key. Make the appearance that you aren't scared just inquisitive. She doesnt want to attack you, she would have already done it. She wants to scare you. In this way you will show her you have no fear. She has lost. She may fight you out of anger of losing this battle. Win or lose the fight, doesnt matter you will have one the war. No more power over you. She isnt going to kill you. If she hits you first in public with witnesses she will be in trouble with the law.