How to upgrade to Yosemite without AppStore I just can't add my credit card into Apple Id, I've tried hard, really.

I've manage to find a way how to install xcode, new iTunes and so on, but still not last OS upgrade. I've found information about downloading ISO and performing a clean install, but I don't want to loose my settings and everything.

Is is possible?
I have AppleID account without Credit Card.



It works just fine in getting latest updates like Yosemite.