Know that you aren't alone with these feelings? In fact, for instance here at PC, those in deep distress are to be told to call their T or go to the ER BECAUSE most of us here are not able to really "help" some people...
But by listening, yeah, that's good. And you want to give back something too...most of us do want that too...
I had a very accomplished musician ask me recently how to counsel those who came to him with all sorts of issues and he had no Christian counseling training etc... I think some of that is applicable here: Ask them what have they done to try and feel better or make the situation better? What did they want done? How can I help you? (Of course when he was working with believers, it was what did you want GOD to do?)
That shows that you want to help (and if they ask for something you can't provide, tell them you aren't qualified or such

but if they think of something else to let you know ).
Asking questions like these helps her focus on a good outcome and options rather than stay muddled in the mire. And it helps her realize that maybe she hasn't done much in the way of helping herself.
And if you really think you can't offer anything but empathy, then say so! Just being there is often good for another.