I dated a person I believe to have BPD, not diagnosed though, not suicidal either.
The self harm thing is a serious concern, it should always be taken seriously.
this article has a section on what to do when someone is feeling suicidal (third section from the top I think it is)
It can be a really traumatic experience, so its good to have support: family, friends, us here on the boards. Keeping connected can help you stay centered, you don't have to go it alone.
She will need to work through her own issues, and you can support her if you really feel up to it, but just keep in mind that you can't "fix her", nobody can really, but that doesn't mean there's no hope for her either.
As for getting unstuck, talking about the choices we have to make and saying the pros and cons of each usually helps to narrow them down and make it easier to choose a path.
What are your thoughts on the situation? How did your inner debates played out? also valid is: would you rather not make a choice right now and wait and see how it develops before doing anything else?