Need’s advice with the next step! Help!

I have seeking a Network Admin position, and have been looking for over 3+ Months. I have gotten an interview for a position and the hireing manager told me I was exactly what he was looking for and at the end of the interview invited me back for a second interview. He said the HR rep would be in contact with me within the day or next. I wrote a thank you letter, and a week later I have yet to hear from them. I sent an email to the IT manager(who gave the interview) as well as the HR rep. Still I have heard nothing. Should I call? I do not want to seem too eager or annoy my potential employers.