Windows experience index means almost nothing, don't worry about it. Only one core gets tested with the WEI.
Did you mean GPUz?
It's shows 1gb because it has 1gb per core. It's literally two of everything crammed onto one card, the memory is not shared it's two 1gb's. At the bottom left of GPUz, there's a little drop down menu, there's should be two and also crossfire should say enabled 2 GPU's.
EDIT- Ihatethedukes beat me