There are a whole lot of questions to this.
-What is her profession
-When does the symptoms arise
-What is her posture
-What does the cervical movement testing reveal. You said that there is end range pain with extension. Have you done extension from a retracted cervical spine? That is how it should be done to get a full range of ext. But be careful when you check this. Lack of cervical proprioceptive stimulation can also cause vertigo like symptoms.
-What would be the size of the pillow she uses
-Are there any am/pm variations to it.
Traction need not be given in this patient. The results you are getting now would be temporary if the cause of the vertigo is not removed.