My Oranda Goldfish has buoyancy problems and fungus, how can I cure it?

For about a month, my goldfish has been having swim bladder issues. She's been upside down floating at the surface. She eats well and tries to swim to the bottom every once and a while, but she can't stay upright. Before the swim bladder started, I had finally got rid of the Septicemia she was infected with. I have well over $100 invested in my goldfish. She's a pretty tough fish, and she's been through about everything. (Dropsy, Tail rot, Septicemia, Swim Bladder, and now some fungus) Is there any way I can cure her of her illnesses? Are there fish vets that I can take her to? The fungus on her is white and looks fluffy. I've added some fungus medication, but there's been not improvements. It's been getting worse, and it's spreading from her tail to her head. She's very stressed. Every week I do a 50% water change. I've been told that there is no cure for buoyancy problems and that I should just euthanize her. I can't bring myself to kill her. Should I try gently scraping off the fungus? I've been getting different answers for that. Some sites say "Yes, absolutely remove the fungus" others say "No, it will only worsen the situation." Please help!