Don't throw it in the garbage. You can either recycle it or save it to use in another craft project.
Paint the water bottle pink and let it dry.
When the paint has dried, use scissors to cut strips in the bottle. Start at the bottom and go up to about 3 inches from the top, just leave enough room for the head.
Cut a strip of pink felt to cover the top of the bottle and glue it in place. By the way, you should have saved the lid too, for another project. ;) Always save your lids, they are great in a pinch and don't take up much space!
Cut a long strip, about an inch in width, from the remaining pink felt. Tie that strip into a bow. Trim the ends and glue that to the front of the pink strip around the mouth of the bottle.
Now just glue on some eyes and use markers to draw on some lips and cheeks! Done!
Oh, you can hang her by adding some yarn to the top of the bottle. :)