Paperwork to foreign consulate

[cep81]

So I just completed the biographical data sheet, which is the last form I (the US citizen) have to complete for the Spouse Visa. The NVC said they will review all paperwork (takes 4 weeks) then send it to the US Embassy in El Salvador. Once it is in El Salvador how long will it take for my husband to receive info on his medical check and interview? Also, can I (the US Citizen) attend the Visa Interview with him? Anyone give me a time frame of how long the interview process will take? We are very nervous about the interview.
Thanks for ANY response!