If by "the kext thing" you mean installing kexts after system is installed, get kext helper or osx86tools and you can install kexts with point a click. If you install wrong graphics kext you may stop the system from booting so you need to find out how to recover from that, the easiest way would be using windows and macdrive, deleting the non-working kext you have installed and reboot with -f flag so the kextcache gets refreshed.
For the graphics mobile cards are sometimes different so maybe standard EFI Strings wont work for them, I would try maybe nvinjectgo or natit (not sure), remember to remove the EFI String first.