You can do it yourself.
This was from my experience of renewing the spouse KITAS. I am going to guess most of the documents(listed below) are the same, but check to make sure.
1. SKTT (Surat Keterangan Tempat Tinggal)
2. Buku/Akta Nikah (Marriage certificate)-Both Church and local government
3. Surat Lapor Nikah
4. KK Sponsor
5. KTP Sponsor
6. Your passport and copies of all non-empty pages.
7. Surat pernyataan dan jaminan - download here and fill in https://goo.gl/14iaSA Print out, affix 6000IDR materai stamp and sign (in name of Indonesian citizen) which must go partly on top of materai
8. If married in Indonesia, a certificate of no impediment from your embassy (note: should be obtained before marriage!)
9. Surat permohonan - download https://goo.gl/RPEJmg and sign in Indonesian citizenship name with materai as above.
With items 7 and 9, be sure to change the top portion to that of your local immigration office that you are going to.
They often ask for a Surat Domisili too.
Usually procured via Rt/Rw & kelurahan [Credit to Bad_Azz]
https://forum.expatindo.org/threads/renewing-spouse-kitas.1459/