Should I Call Co-Worker?

There was some talk that an aide was not coming back to fill her position for the following school year, at the school where I work as a substitute. I called the school and talked to the administration, and I was told that she did not quit yet. Now, the people I heard this “talk” from are reliable people that I work with.
I would like to know if this person is planning on leaving because I am interested in her position. The school and school board have known for months that I am interested in the job full-time. I have made calls to the school itself, wrote two letters of interest, had a letter of recommendation sent, sent my references to them, and I talked to a school board member.
I have been searching for other jobs in the meantime, until further notice, but I really want this job. My family thinks I should call my co-worker and ask what her plans are. I’m not sure if I want to do that. Is it any of my business and not my place to ask or should I call? If I call, how should I ask her?
If she is planning to stay, I don’t want to keep wasting my time hanging onto this position.