I know what its like to be frustrated by co-workers. I work with another of the take credit, talk all day on the phone people. I'm both management and an EMPLOYEE so I'm kinda stuck.
However, you have done everything correctly
--you've tried to handle it yourself and it really is time to go to the boss. You may be surprised to learn that they HAVE noticed that the phone talker isn't doing her work and IS taking credit for your work. Sometimes you just need to let them know that not only is the phone talker's attitude and work habits affecting you and your work, it is affecting the professional reputation of the office.
Good luck and I hope things get better for you.