Without going into much detail I would hardly say that the 560M is gimped.
Here are my specs:
ASUS G74SX-DH73-3D 17.3-Inch 3D Gaming Laptop
Intel Core i7-2670QM Processor
16 GB DDR3 RAM
1.5 TB 7200 rpm Hard Drive
17.3-Inch Screen, Nvidia GTX 560M 3GB GDDR5 Graphics
Windows 7 Home Premium 64-bit
I don't know if it relates to Kingdom of Amalur but I play SWTOR, BF3, and MW3 exclusively on this machine and I have everything maxed out on each game. I know it sounds strange but it seems that SWTOR is the most inconstant as far as fps goes but I believe that has more to do with the game engine that Bioware used and server side issues than the client side. That said I get fps over 100 in most areas with the exception of heavily populated areas in the game and huge pvp matches and even then the fps never drops below 40. Being that Kingdom of Amalur is a single player game I wouldn't think you would have any problem at all running the game.
I hope this helps in your decision.
Cheers!
ASUS G74SX-DH73-3D 17.3-Inch 3D Gaming Laptop
Intel Core i7-2670QM Processor
16 GB DDR3 RAM
1.5 TB 7200 rpm Hard Drive
17.3-Inch Screen, Nvidia GTX 560M 3GB GDDR5 Graphics
Windows 7 Home Premium 64-bit