So I updated my computer, and now I've got a good processor. It came with a video card that I can get max settings with over rural terrain at 24 FPS, but I'm considering upgrading. This is the data I found on the card I have now:

The GT 530 is an entry level OEM card with :
CUDA Cores : 96
Graphics Clock (MHz) : 700
Texture Fill Rate (billion/sec) : 11.2
Memory Clock : 898 MHz
Standard Memory Config : 1 GB or 2 GB DDR3
Memory Interface Width : 128-bit
Memory Bandwidth (GB/sec) : 28.8
NVIDIA SLI-ready : Not supported
Maximum Graphics Card Power (W) : 50 W
Minimum Recommended System Power (W) : 350 W

This is the card I'm looking at:

GTX 560 Ti 1024MB
Product Specifications
Core Clock      822 MHz
Processor Cores      384
Processor Clock      1645 MHz
Texture Fill Rate      52.5 Billion/sec.
Memory Amount      1024MB GDDR5
Memory Data Rate, effective      4000 MHz
Memory Interface      256-bit
Memory Bandwidth      128 GB/sec.
On-board Outputs      DVI, DVI, and HDMI mini
Bus Type      PCI Express® 2.0

I know from just looking at it that the numbers are much, much better, but in practical terms, what difference am I going to see in the game? Is it a worthwhile upgrade?

Thanks!

Yup I'd agree with that. The 560 is a good midrange GPU choice, fine for FSX. Also I'd recommend 8gb RAM if you haven't already. What exactly do you mean by a 'good processor'? Remember the CPU is the most important factor in FSX performance.

Sean