First of all, can you please share your test results for ammonia, nitrite, nitrate, and pH? Exactly what fish are in your 5 gal? How long has the tank been running?
The basics of treating ich involve adding meds, slowly turning the tank up to 84*, and adding aquarium salt if your fish can tollerate it. Your mollies can, but i don't know about the rest of your fish. Also you need to make sure your water quality is excelent, as it gives the fish a better chance.