I agree, Plan "A" is getting chicks. As mentioned, create a brooding area for them within the coop. Older chickens, in general, are usually very tolerant of chicks. And, once she sees them, she would know she is not alone.
Plans B. If you can't get chicks (which is tough this time of year) maybe check out Craigslist for fertile eggs and invest in, or borrow, an incubator to hatch your own.
Plan C would to spend as much time as is feasible with her, so she has some company and interaction, until you are able to get chicks.
Plan D would be to re-home her to a person with a flock that she can be added to.
All and all, it is a tough situation. I hope you are able to fine a good solution.