Sounds like you do the same line of work? She needs to immediately start getting medication for it, if she wants to survive. It's not necessarily a death sentence, but she will need to use protection. If she doesn't tell her clients and doesn't use a condom, that could bring up some legal issues. Look at local centers that can at least help. If she isn't ready to give up doing tricks, then at least start slowly with the treatment and getting help.
She really needs to stop prostituting herself out and get treatment.
Help her check into programs that will help her financially/medically. Let her know you still love her and will be there for her (assuming that you will be).
What about her clients unknowing partners? It's that attitude that continues to spread the disease and the reason your friend now has to deal with this. Frankly, I don't know what you ought to do if she won't take the responsibility upon herself to protect others. You are in a tough spot and my heart goes out to you and to your friend. I do know there are some programs to help women get out of prostitution, but I don't know what is available in your geographical area. I attended a dinner for nominees for volunteer of the year some time back and the number one volunteer had been a prostitute and had a non-profit that specifically helped other young women get out of the life style, so I know for a fact that such programs do exist -- at least in some cities. If I remember correctly, this program was in Portland, Oregon. It was J.C. Penney who gave the volunteer awards. I just write this in case it can help you locate what you need where you live.