Changed graphics card - now no graphical enviroment

After installing fglrx using 1-click install I indeed get to the text-mode. Recovery mode also throws me into text mode, on my system recovery mode took me to a graphical mode.

I will try the instructions above and get back here, thanks !

Recovery mode should still work with fglrx installed, even when fglrx is not working.
So it would be even more interesting to see the Xorg log.

Maybe uninstall it in text mode with:

sudo rpm -e fglrx_xpic_SUSE131

or

sudo rpm -e fglrx64_xpic_SUSE131

respectively, and then post /var/log/Xorg.0.log.old after a successful boot.

Ok,
When I update the kernel from that repo, do I need to update the versions of kernel-devel, mkinitrd, kernel-source, kernel-firmware, etc too, or just the kernel-desktop package ?

As I said, you should update kernel-firmware as well, as that repo contains an updated version.

The rest shouldn’t be necessary, as long as you don’t want/need to compile kernel modules for the new kernel.

But better add that URL as repo in YaST->Software Repositories, necessary packages are then installed automatically.
But still, you would have to update kernel-firmware manually.