It is possible to run the game in window mode at acceptable resolution. 20" window is enough to play. I would try 1400x1400 window to be able to see instrument panel.

If the new card is adopted for new 2012 series macs then there could be a chance for 2011 series support? I won't get my hopes up, I know it's unlikely.

Not sure what you're asking but changing the graphicscard on an iMac is only for pro...and it will cancel your warrenty plus the extra power will generate more heat and might mess your iMac up.
Also remember that the graphicscards fitted in the iMacs are the mobility type thus lower performance compared to regular ones.

What you got is what you got. But when we get the next patch with the remedelled 3D engine then both u and I will be able to fly with decent frames.
Until then you have to fly with low/med settings and tweak the system.

Overclocking gave me 10 more frames but I can almost hear the mac squeeking from the heat. There are safe overclocks where u might get 5 more frames but you might as well wait for the patch.