Alright then...
Easiest way to do this is....restart the install. Follow my guide, using this new method :
Using your Unibeast USB and with monitor in 1st DVI on Nvidia or HDMI, boot into the USB with -v -x GraphicsEnabler=No npci=0x2000
If you have set the video BIOS settings to AUTO and memory of 64MB or more, this WILL boot the installer.
2) In the installer use Disk Utility to FORMAT the drive as Mac Journaled HFS. Make sure it has GPT/GUID partition.
3) Install OSX 10.8.2
4) When it is finished, select your MB 5.1.3 requirements including USERDSDT, Without DSDT Realtek ALC 892 and whatever other kexts you need. Also add AppleACPIPlatform rollback. For graphics select the 3RD OPTION FOR YOUR NVIDIA.
Then INSTALL LATEST NVIDIA GEFORCE MAC DRIVERS and shutdown. Install your Nvidia card and reboot with -v -x GraphicsEnabler=No npci=0x2000.