Fungus has caused a huge bare circle in my yard.

It could be grubs instead of a fungus. You will need to treat the entire lawn next spring, I believe.

If it were me, I would kill it off with vinegar, then dig out. In the spring, till over and amend heavily then overseed with grass appropriate for the area. Also check with the Master Gardener at a local nursery or your local Ag Extension.

http://homeguides.sfgate.com/kill-fungus-grass-41924.html

I have done all that is suggested. Still have it. Store remedies too. Still fungus. Wondering if there is something herbal/organic that willmwork.

Vinegar....mmm. I shall try that. Should I do that now? November? Or wait till spring to do it all.