This is definitely "The Girl With the Silver Eyes." I have the book, and I just reread it a few weeks ago.
The girl's name is Katie, and her eyes are, as the title notes, silver. The powers come from a painkiller drug that her mother used along with three other women who got pregnant because of it, who are the other children with silver eyes. The drugs apparently genetically modified the children so that they would have those powers. Katie is telekinetic and can communicate with humans, cats, and possibly dogs with her mind.
Mr.C, or Mr. Cooper, is not her stalker, but rather a guy who works for the Institute of Paranormal Powers and wants to make sure that Katie is truly a person with paranormal powers and not a charlatan (the definition is in the book).
She was accused of killing her grandmother by the Armbrusters, but the police never came for her because of that. She thought they did, though, so she ran away. She already knows Dale at this point, and then she communicates with Eric with her mind, assisted by Dale, and they meet at a fountain. They three go to Katie's home and find that Kerri is there with her parents, as someone who knew about the peculiarity of all four kids had called a meeting or something of the sort (it was never revealed how the parents came together then). The kids, now with a Kerri that clandestinely slipped away "for her handkerchief," walk into the meeting and things are explained.
Any memory recall? Do you remember now?