How many times should one put down the fungicide? I did it about a month ago and it doesn't look like it's improved.
I do it once a month, you can probably do it less for maintenance but in your case I'd probably do it again now and in another month. It won't hurt anything if you use more than you actually need. It will be slow to recover, the grass is dead and with the cooler weather it will not grow back quickly; maybe not until the spring. The main thing is the fungus is not spreading. I lost over half of my lawn to it a couple of years ago and it took from the spring to the fall to recover.