Yoda; Firstly i think you are definitely proceeding down the right path by letting her open up to you in her own time.
I think there are a few main things you do need to reiterate to her though, because this is never going to be something she forgets, she can only hope to deal with it in a healthy, positive way.
She needs to know that her value as a person and a woman is not diminished. For someone from the kind of (cultural and social) background that you describe, the hard slog is a point of pride, not something most want sympathy for. For her to make all those hard choices she must place a lot of value on intimacy and have high hopes for her future relationships. ENSURE SHE UNDERSTANDS THAT THIS UNFORTUNATE EVENT CANNOT STOP HER FROM HAVING MEANINGFUL RELATIONSHIPS.
Do not let her blame herself and reinforce that IT IS NOT HER FAULT. Regardless of how she was dressed, or who for or where she worked. Or any variable that came into play in this situation. Make sure she knows that THESE ARE THE JUSTIFICATIONS A RAPIST WILL GIVE HIMSELF. She knows that 99% of people will not look at any of those things as provocation.
Make sure that because of this she doesn't BEGIN to make bad choices for financial support. You want this to be something she will OVERCOME, because it will make her a damn tough cookie when she eventually gets past it. The last thing you want is for this assault to be an excuse for her to let things slip, as in, "Well someone else already has so i may as well let you do it too" HELP HER TO AVOID THIS TRAP AT ALL COSTS.
Keep strong for your friend - Sometimes even the strongest most capable women meet hurdles they cant jump on their own.