Chosen Solution

I have a: iMac 9,1 24-inch, Early 2009 Processor 2.66 GHz Intel Core 2 Duo Memory 4 GB 1067 MHz DDR3 Graphics NVIDIA GeForce 9400 256 MB Can the graphics card by upgraded?

No it can not. the GPU on these is soldered to the logic board VIA a ball Grid Array. It can be replaced should it go bad but upgrading is out of the question.