The yellow in your dog's vomit is bile. Dogs vomit more easily than you or I because of the way they have evolved. It is thought to be a protective mechanism because they will eat anything and that is not always good. Vomiting up to once a week may be normal for some dogs. If it occurs more often, please see your vet.
Ear infections can be very difficult to treat.
This is too painful to be done well when the animal is awake. At-home care is very important, though very time consuming. Those ears need to be cleaned and treated daily. If the infection subsides, the ears must still be cleaned for the animal's lifetime. For infections that do not respond to medical treatment, surgery is the only option.