Hey there sweetie, I'm so sorry to hear that you're going through this. Your dear girlfriend sounds like she is sufferent from PTSD (Post Traumatic Stress Disorder) from her rape. This is treatable and you are wonderful for wanting to love her through something so difficult. It is treatable but one thing you did not mention that is a major factor is her willingness and strength with regards to getting treatment. If you find a good therapist, they can really help... but people must be willing to work to feel better. I don't know where she's at with that. (Please keep in mind that 1.I'm not yet qualified to diagnose officially and 2.If I were I still don't have the whole picture. I believe she needs help with regardless of the accuracy of my proposed potential diagnosis.)
In conjunction with this, a therapist with some knowledge in sexual therapy may be helpful in that area. Some methods of treatment in sex therapy have to do exactly with no strings attached foreplay, purposely designed for many reasons such as reducing tension and anxiety involved with sex. The two of you could talk out and agree upon ways to get affection without sex and to work with her at her comfort level. But right now she is psyching herself out about it.
She could be helped - the real questions are WILL she and will she do the work, and then do you want to be there for her through this ordeal. If both the answers are yes, maybe you can regain what you had and something deeper. If not, my condolensces for your relationship and life will work out okay anyway.