Just an update - IT WORKS, and the setup was simple!
I used the card mentioned in the post above and hooked up the AVR and the TV separately using 2 HDMI cables and I was done! I had to switch the GPU from PCI-e to on-board in my mobo BIOS, becuse when you plug in a PCI-e GPU card the Mobo automatically switches your video out from the on-board to the ports on the card, which is not how I wanted it so I had to switch it to on-board there, and disable crossfire to ensure they both act as separate GPU's and not as one. Mine was already disabled, probably because the HD 5xxx series is not the right crossfire card for a A6 APU, I think it has to be a HD 6xxx card.
Anyways, long story short I did this and adjusted the screen size as windfire has detailed above, pretty straight forward, thanks again windfire (+rep) and now I have HD quality picture and sound from 2 different ports and I can use the 67" screen to surf or watch HULU web only videos
- which is pretty awesome! The picture is now completely filled on the screen and the sound is in 7.1 if your media supports it (eg; Blu-ray).
The only issue (not a big one, I can definitely live with it) - is that now the image on the screen is tilted upwards a bit (probably 1/10 of an inch). Which doesn't affect most of the stuff that I do, just when I go to close a page the part of the X sign at the top right is slightly cut off, anyone knows why?