Any time I got stuck in any of the steps my sponsor would tell me to go back to the 3rd step. Get on my knees and reaffirm that my life and will were under God's care, and then move forward in trust. 8th step requires that we become willing, which it seems you are. 9th says we make those ammends when we can do so without injuring "them or others". While you didn't say so specifically, I'm going to guess that this is sensitive because it may hurt your sister, or someone else.
My experience is that as long as I am willing and trusting that I'm being guided, the right time, actions, and words witll present themselves. I have more than one instance where I made ammends I never thought I would, and at completely unexpected and unplanned times. As long as the willingness is there, I believe the rest will work itself out. I'd say move on with the rest of the steps. And be open to whatever opportunites regarding this are put in your path.