AleksandrM,
Each program operates a bit differently, so the answer to your question depends on the school in question.
For example, if you interviewed with Columbia Business School, hearing within two weeks of the interview (if not sooner) is very standard. If you interviewed at Harvard or Wharton, there is a set date where decisions for that admissions round will all be released - regardless of the date of your interview.
Based on the information your interviewer provided, my sense is that "shortly" should mean a couple of weeks. Of course, interpreting this comment depends on who your interviewer was; if she was an admissions officer, I'd take her word and expect a decision promptly. If she was an alum, she may not have a full understanding of the process and could have just been throwing a rough estimate out there (since alums aren't typically tied into the operational details of the admissions process post-interview).
In all cases, I wish you the best of luck in this process!
Hang in there,
Graham
