Responsive Classified – Update help please

Hey guys, I´m using Responsive Classifieds Theme version 6.3 and WP 4.0.. I´m also using a child theme. I read, that there´s no auto update for the mothers theme?!

I tried to download the latest version from my member account and to install it as a new theme – i didn´t work.

Could someone please tell me how to update without losing files and data???

Thanks a lot guys!!!