How do I cope/help with a partners rape?

I have been dating my girlfriend for almost 8 months now. It is a sexual relationship. I knew that a relationship she had very recently prior to me was sexual as well, but after dating for a few months she opened up and told me that she was raped. I was so enraged that I had actually planned to kill the rapist. I eventually calmed down but the anger and sorrow never went away. I was only slightly comforted by the fact that she told me she had lost her virginity to another man. However, about a month ago she told me that she was lying to me and herself, and the rapist took her virginity. I was even more enraged this time and I still feel the anger burning. I go through phases when the anger is dormant but I still feel it festering. But above even the anger, I feel great sadness for my girlfriend. She has been permanently traumatized by this and it is noticeable. I can see it when she flinches at certain movements or certain things scare her to the point where she just hides her face and doesn't talk. What can I do when all I want to do is get revenge on the man who did this, who I know, have met, and talked to? I just want her to be happy, but I know she can never completely recover. Are there any tips on how to cope with this, both for me and her?