Why dont you just keep your 4870x2?
I dont think think You'll have any problems maxing out Mass Effect 3 with it.
And if you still want to upgrade it will be better to just wait for AMD 78xx series.
Like I said on the OP the 4870x2 went kaput it no longer shows an image on the screen with the message VGA BIOS being displayed on the board LCD. I guess I will have to wait until the new AMD become available then