If it's night she probably won't go very far. She'll probably land somewhere (hopefully in a tree where she'll be fairly safe from predators) and stay there until morning. Make up some "lost bird" flyers and post them around the neighborhood, and as soon as it gets light go out with Rocko in a cage. If he calls, she may hear him and come to him. Have as many people as possible traveling around the area looking for her. Have something available that could help you catch her, for example a light blanket or towel that you can throw over her. But move carefully, you don't want to spook her into flying away again.
When she flew away, was there a leash dangling from the harness? If so, it could get tangled up in something. That could be dangerous since she could get trapped somewhere, but if you're very lucky she might get tangled in a place where she's not in danger and you can reach her.
You can post on parrot911alert:
http://www.911parrotalert.com/ Do you have something like craigslist where you could post a "lost bird" notice online? The more places you can post, the more likely it is that anyone who finds her will be able to contact you. If you can offer a reward to anyone who finds her it will help motivate people to look for her, especially if you have a lot of children in the neighborhood.