I have had a similar problem. When I see another dog approaching we stop and sit off to the side. In most cases I choose to not have the dogs meet. As the dog approaches I'm kneeling beside my dog - not bent over. Bent over is apparent a signal to a dog that they need to protect us - thus barking. As I kneel beside her her I pet her for good quiet behaviour and tell her to just watch the puppy, no barking and those kinds of words. When the dog passes successfully I tell her good girl with lots of praise.
Other times when passing dogs in the neighbourhood I sternly tell her "leave it" and sometimes tug on her leash.
Another training is the "settle" command. At home take her snout in one hand and rub your finger up the side to the ear and then switch hands and do the same on the other, while saying "settle". Do this now and then each day. Don't let go of the snout and do it about three times on each side. What the dog will learn is that it's all okay, you have taken control, she doesn't need to dominate or protect. Eventually she will associate the word "settle" with the action. Hopefully, then just issuing the "settle" command will help her quiet down.
I would say... take her back to the dog park... they say that a dog's behaviour comes from something that we are doing wrong and I would say that the dog misses the park and the other dogs.
Hello, I am a Lab owner, really dog lover.
Get a plastic spry bottow, the ones you can get at a beauty suppy store, or for watering plants, and fill with water, when she barks just dont say anything to her just look at her like as you were disaproving her behavior and spray water in her face. Good Luck!!!