Oh no, I hope she comes back soon and safely!
I've heard of people having luck by putting something familiar outside, with hopes she follows the scent. Maybe a bed if she has one and a t-shirt you wore? Sometimes outside cats can get into fights and become disoriented, and the theory is the scent helps them find their way back home.
Also, flyers and newspaper ads! I'd also alert any local shelters and vets, maybe send them or show them a picture and let them know she is microchipped and belongs to you.
My cat, Melanie, was missing for like a week once when she was little. She ran outside while my aunt was in the door or something. I'd walk around and call her name and I was so upset. She came home in the middle of the night, while it was pouring down rain, with not a drop of water on her. No idea how. My mom woke me up to give her to me.

I hope Oprah's story has a happy ending and she finds you again soon!