So what i have done is installed Enabler (Enabler_for_Nvidia_and_multiple_ATI_cards.pkg)
And with efi studio i have generated hex for GTX260, and instaled it with osx86tools.

The system is recognizing card (about this mac)

nVidia GeForce GTX 260:

Chipset Model: nVidia GeForce GTX 260
Type: GPU
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 896 MB
Vendor: NVIDIA (0x10de)
Device ID: 0x05e2
Revision ID: 0x00a1
ROM Revision: nVidia GeForce GTX 260 OpenGL Engine [EFI]
Resolution: 1280 x 1024
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Display Connector:

but in display dialog i only see one resolution which i have defined in osx86tools.

i have a problem with dual monitor. it's not working...

can someone help?pleassssseeeee?