Ciku

Hi
I am from Australia, so unsure if the process is the same in your country.
But my 15 year old daughter was a follow to join 9 months after I arrived in the USA. I contacted my consulate and they gave me instructions.
The process was the same for her as it was for myself and my son when we came over beforehand. The same forms, same other parent (father) permission to leave the country, affidavit of support, medical, interview. It was the same for her was it was for us.
As she was 15, she signed her own forms, but younger kids can have a parent sign.
The process time was a bit quicker for my daughter than it was for us I think.
Once she arrived in the USA we submitted her AOS paperwork and she received her greencard in the mail. In our case she was not required to attend an interview for this, but she DID have to have the biometrics done.
Sorry I don't know more about your particular embassy, but I hope it helps in some small way.
I wish you all the best, and a quick and easy process to bring your son to you.

K-2 Visa Application Process
Your children will have to go through the same (or a very similar) application process as you. At the beginning of the application process, all the U.S. citizen sponsor needs to do is to include the children’s names on Question 14 of the Fiancé Visa Petition (Form I-129F). The consular officials should then send extra sets of the required forms for the children to fill out. If you do not receive these extra forms, contact the consulate. For young children, it’s okay for a parent to fill out the form, and even sign it, on their behalf. (Just sign your name, then write Parent of [name of your child].)
The children will have to prove that they are not inadmissible and that they will be financially supported along with the immigrating fiance. Each cihld will need to show proof of their relationship to the immigrating K-1 parent, such as a birth or adoption certificate. You will also need to gather many of the same documents for the children as you do for the main applicant, such as medical reports, photos, and passports; and to pay individual visa fees.
After you get married and apply for a green card, your K-2 children may apply along with you. Each will need to submit (by mail) a separate application for adjustment of status to U.S. Citizenship and Immigration Services (USCIS).
See this thread too
http://www.visajourney.com/forums/topic/347113-k2-visa-process-for-child-of-fiancee-k1-visa-beneficiary/

Thoroughly rude and un called for response to someone trying to tell you the reality! Sorry if it is not what you wanted to hear (and I am typing on a mobile so some misspellings) I worked for HR in retail and I am telling you what the retail industry sees. There are moms who apply for mommy hours (days only, no nights or weekends) so they were not called back. Weekends and nights are when it is busy and when we needed clerks. If you want to work in retail, you need to be flexible (and seems you need an attitude adjustment too) I won't say good luck because you are obviously above that... So enjoy more time sitting on your bum waiting for a job to call.