Don't feel like you're bothering them. You had a plan, but you cannot get the right meds, so you need a new plan. I don't know the people there, but they seem both knowledgeable and caring, and will understand the bond that keepers form with a fish like an Oscar. It's worth a shot.
I can't make false promises, because I have no idea what is happening here, but I do urge you not to give up hope, even if it looks very bad right now. She's showing a lot of life still, so the battle isn't over. Have seen fish recover that you would swear couldn't survive, including one that was on its side on the bottom of its tank, bleeding a lot and barely breathing. Yet it recovered with the right treatment. A youtuber I like a lot found a small fish on the floor that had jumped out, and it was almost dried out. He held it with its face towards the filter output so water flowed over its gills, and held it there for 15 minutes as it slowly revived. Saw the video footage he took. Like fish CPR.
I almost lost my elderly dog last month. He went downhill rapidly, and I was devastated, convinced we'd lose him. Vet said either a very bad stomach bug that could kill him, or his organs were failing. She was very sympathetic, and warned me that it didn't look good. At 14, with the health problems he already had, I was absolutely expecting the worst, and I think the vet was too. I had to nurse him and carry him down the garden, beg him to eat and drink. He recovered and is doing so well.
Don't give up hope until it really is too late.