Once you finish the medication, focus on keeping your water parameters as neat as possible (say nitrates at 10 or 15ppm).
By the way, as far as I know, API Fungus Cure is likely to disrupt your biological filtration, the water colouration is expected and shouldn't stain your tank in the long run but could ruin some decoration.
I guess you noticed this early. I haven't faced that problem yet but read here and elsewhere that if treated timely it should heal well.
Some fishkeepers use medication as a last resource. Personally, if my water parameters are in check -and I put a good work in keeping them there- I jump the gun early and treat with broad spectrum gramm positive and gramm negative at the same time, dosing twelve hours appart if I found to have solid basis to suspect bacterial infection. For that to be cost effective I use a Hospital tank. It gives me the benefit of keeping their home tank stable cycle wise and reduces my load of work even if I need to perform frequent partial water changes since it is a much smaller tank.
I am glad you are getting a bigger tank, in the meantime, improve your filtration system if needed. You could complement the regime by feeding them Spyrulina based food -allegedly enhance their immune system.
Please wait for others' feedback.
Pepe
Santo Domingo