That's great that you're giving echinacea, but I can tell you that it will not "cure" your rats. Echinacea is merely an immune booster, it in no way actually attacks the illness that your rats are fighting. What echinacea does is help strengthen the immune system so that becoming ill again is perhaps decreased somewhat.
The only thing that can make your rats well is antibiotics, which you can only get from a vet. It sounds like your ratties could really use a vet visit...could you ask your parents to help you out?
They might be more willing to help if you explained that your pets could die without veterinary care. Respiratory disease (mycoplasma pulmonis) is fatal if left untreated, and it's a very painful way to die that can easily be treated by a simple run of antibiotics. Though a vet who has experience with rats is a plus, any vet can prescribe the medication your ratties need.
Happy New Year, and I hope you can get your rats to the vet soon, their lives could depend on it!
