Hi, Meeee1111. There are several online store for Kebaya in Indonesia. But I am not sure if they have Haute Couture Kebaya on their list or not. Many of Haute Couture Kebaya in my Hub designed by Anne Avantie, so the most possible way to get it is by visiting her boutique.
Here is her Address: Mal Kelapa Gading III Lt 1, Jakarta, Indonesia
or you can make contact with her through email at firstname.lastname@example.org
Another page which maybe available to make contact with her management is http://www.anneavantie.com.
Maybe you can ask them how to get their Kebaya.
I hope this helpful. :)
Have a nice day.