My friend is herion addict and and aloholic?

Im in a really tough situation, and i'm not sure what to do. Four the past 5 years, my friend has been struggling with alcoholism, and on top of that she is a herion addict. Im worries sick about her. She recently went to rehab and was released and was supposed to check into an outpatient treatment, but she just disappeared from here house last night and nobody has heard from her. I'm worried sick, because before she went into treatment, she was stating that was going to kill herself on several occasions. She swallowed a handful of prozac before in an attempt to commit suicide, but thankfully she made it through. I am worries sic about her and I cant stop thinking of the worse possible scenarios. I have spoken to her mom and the only was I can describe her is broken. Shes exhausted and she is blaming herself. I have a problem. I moved away for school and I live 500 miles away. As much as I want to go down there and go on an all manhunt looking for her, I just dont have the money. I'm not sure what point im getting at, or what I expect people to say. I just need some advice, maybe some websites or something. I feel as if I should be there for and that i'm letting her down. Is there anyone who has been in a similar situation where the person actually got help. Our friendship has caused me so much stress and i've lost countless hours of sleep worrying about here, but I love her too much to give up on her. We are practically family, and im not sure how i would handle loosing her. Im so afraid that one day i'm going to get a call from here mother,telling me that she overdosed and ped away. I'm scared to death about what might happen to her. She's already been ually aulted before, twice, while under the influence of drugs and alcohol. Any advice ?