Hey everyone: It's Gia's mom again.

Gia has a habit of barking at people that pass by our huge office window (sometimes it's just a blowing leaf). She also seems to bark at children now (pout!) and passing cars.
I have tried positive reinforcement, coins in a can, and the water gun... nothing seems to stop her. She's a sweet little girl, but she just seems to go bananas when these few things happen. (Obviously, she barks when someone knocks at the door, too, but that's seems minor compared to the other barking).
Is she stressed?? Am I doing something wrong? Her little heartbeat just gets going and she just seems so freaked out when this happens. I'm not sure what to do to fix it...?
PLEASE PLEASE HELP!
Thanks,
Jenn