Doberluv pretty much spelled out the whole RRR issue. Never call brownie to come unless you would bet a hundred dollars that he/she would. Calling "come, come, come" just wears out the command and teaches the dog she can ignore you. Try practising the come over and over again during the day ie come for dinner, come for a treat, come for some fun play, come for a walk. You can build up the distraction bit by bit. This may take a while, especially the first time you introduce a big distraction like another dog. If Brownie does refuse to come after the first calling, go and get her yourself, don't wear out the command.
Teaching Heel is much more difficult than teaching come, in fact in my experience it would be the hardest excercise to teach. Heel requires 100% concentration from both handler and dog. Old schools taught this method with a joke collar and alot of yanking. Positive methods, however, produce better heeling and a much more attentive dog. Start with your dog on your left side, prefferably in a distraction free room or passageway. Have your left hand loaded with treats, the lead in your right. As you start off, do not say heel, use only your bridge words such as "yes!", or click if you use a clicker. Some dogs require near constant feeding when they first start out, this is ok though as you will eventually have them off the food and following an empty hand.
