Just throw it away already. Even if you manage to clean it, there is no way to make sure no spores have made their way inside it and if so, they will spark new fungal growth.
You can,t you have to throw it away I think or just try washing it
Place the bedspread on a deck railing or clothes line outside and spray the entire area with a combination of bleach and water with a spray bottle. Allow to soak for five minutes then wash with a garden hose and allow to dry