Heartworms help!!

My dog is small about 14lbs. She is about 6 years old. She has had heartworms for some time now about 8months to a year. I read the parasite program from Clark's book. It doesn't give dosage according to weight and how long it just says on the 5 th week and so on... Any ideas on this. I saw teh bandit dogs formula but that would be more than vet treatment because she medicated her dog for a year. anything you guys know to do that doesn't take that long? I really would like to go the natural way instead!