|"how to set up dual graphics on fm155-le"|
I believe the board model number is incorrect, please double check & post the correct model number. If it's an OEM system (Acer, Dell, Gateway, HP, etc), please post the model & model number of the system.
"radeon hd6670 graphics card plus 6530 onboard apu"
From AMD: "Once installed, go into the “Performance” section of the AMD VISION Engine Control Center and check the box that says 'Enable Crossfire™' - this will allow the AMD A-Series APU graphics to work in tandem with the select AMD Radeon™ HD 6000 Series GPU installed for increased graphics performance."