I don't believe an HD 8500m is good enough to play those two games at any reasonable level. My laptop has an 8750m which is barely enough to play Far Cry 3 well on low settings (20-50 fps). I don't know much about DAI except it's new. As for FC4, I know AMD got screwed on release, however one of my friends has apparently had good results (desktop with r9 280x). Sorry, but I think you'll have to go a bit higher. My laptop is a fairly new HP Envy with the 5750m CPU and 8750m GPU and cost about $750.
Also, are you actually looking for a laptop or would you be okay with a desktop? Laptops are a fine solution if you don't want to or can't spare more for a monitor, keyboard, speakers/headphones, etc. The problem with laptops is that they have to be kept really cool to actually perform well, meaning you might need a cooling pad (which vary in price but can be found for rather cheap). More details would be helpful.