It’s pretty standard procedure to send updates on employment to the Admissions team, at any university. The fact that your interviewer found out that information during the interview probably meant she knew you hadn’t told the Adcom yet (which makes sense since she didn’t see it in your application).
Also, if I’m guessing correctly, your intention is to either send the email to the interviewer or to the Adcom and reference the fact that you’re doing it because of the interviewer’s instruction.
If that’s the case, don’t stress about including your interviewer’s name since the university already expects you to send updates to them (rather than only upon instruction). Your updates needs to be sent to the Adcom directly,
[email protected].