How Much Is Too Much Follow Up?

Hi T.A.P. Experts, I recently had a second round interview with a large company for a position that I am very interested in. During the second interview, the HR person mentioned that they hiring process might slow down a bit because they were considering internal promotions. After my interview the HR contact left for vacation. Once she returned, I followed-up via e-mail (I also sent written thank you notes the day after the interview). The HR manager responded to my e-mail and said she would know more next week. Next week came and went and I didn't hear anything. I waited a few extra days and then followed-up with a voicemail. She has not responded since. When/how should I follow-up again? How many times and how often can you follow-up with someone? Do HR Managers ever feel like you stalking them? Our Twitter Advice Project (T.A.P.) is no longer an active campaign. To find an answer to the above question, please use the "Search" box in the right-hand column of this website.