I want you to have her call a suicide hotline first. The best thing that you can do for her is make sure she gets professional, immediate help. There is a list of several of the major ones up on my blog here: http://writingsforwinter.tumblr.com/suicidehotlines
Next, have her listen to this recording, which a beautiful tumblr user made: http://fred-erika.tumblr.com/post/43405491042/i-took-three-parts-out-of-the-poem-so-you-want-to
After that, you can suggest that she read these pieces:
http://writingsforwinter.tumblr.com/post/40375447157/i-think-i-am-going-to-kill-myself-tonight
http://writingsforwinter.tumblr.com/post/36040171785/heres-what-you-tell-someone-who-wants-to-commit
That’s all I can really tell you because I am not a professional or licensed to deal with suicidal behavior. The most important thing is that she gets professional help as soon as she can.
Calling a suicide hotline is the best option.
Please let me know how it goes. <3