Treating my betta's fin rot

I followed directions from several websites:

1. Separated from the main tank
2. Changed water in the main tank and washed with hot water
3. Put betta in his old 1/2 gallon tank and other fish back into main
tank.
4. Put appropriate amounts of conditioning salt in both tanks (I wasn't
using salt before)
5. Treated both tanks with Jungle Fungus Clear. If he gets worse after a
day or two I'll move up to something stronger.

My betta has become listless, won't eat and just rests below the surface
of the water. He does react if I approach the tank but he's not feeling
well. Part of his fin is gone and a bit raggedy, he also has a white
circle on his side.

I don't have a heater in either tank but in winter they stay between 75-78
degrees, in the summer about 80-85 degrees.

How am I doing here? Missing anything?
--
Mac Cool