D.W.
Sounds to me like she is one lonely girl. My suggestion would be to sit down with her and explain that friendships for you are not something that can be forced. By her calling daily, she has put a wedge between you and it is getting very uncomfortable. Without hurting her feelings, explain why you don't want her to call you every day/week. Try to put yourself in her shoes and research why she is so persistant.
There are many groups out there...Moms Club International, Mothers and More, etc. that might be able to occupy her time so that she can make new friends. Be a good friend, research her options, and walk away feeling like you've done the right thing. Maybe someday you can be friends.