This chick obviously has a high interest level. If she is calling you and blabbing to you for the better part of an hour, you know that her IL is in the 51+ range, to use the Doc's language.
I think you are in the right frame of mind to be trying to get rid of her and letting her do most of the talking; just need to work a little harder at cutting the conversations short.
The way you should do it is by saying that you are getting ready to go somewhere, at a particular time. You are meeting someone and so you can't talk for very long. Let her blab for a few minutes and then come back with, look as I mentioned before, I really have to go. Where do you have to go? Don't always say that you have to meet another chick; that will become obvious, but do drop that sometimes.
You're a busy guy! You work out to keep in shape, you meet friends, you work, you date, you have important hobbies, you go shopping, etc. If you tell her you are getting ready to meet a girl, be sure that when she calls the next day, talk about how great your date was and the great goodnight kiss and all that ****.
Also, why don't you call her straight on her bull? "Look, why do you keep calling me so much? Are you looking for a boyfriend? You aren't going to get one with all this girl-to-girl chit-chat. I'm a guy, I ain't too interested in a whole lot of talk. If you want to come over, we can cuddle."
Why do you care about not upsetting her? Who cares? It's healthy for people to get upset.
Also, do you not have call display? Where is your answering machine? If you really are a busy guy, you shoudn't even be around to answer the phone. Let your machine take a message. She can blab to the machine, and later you can just drop that erase button on the mf-ing bytch, my homie.