Crossfire question/Sli

Hello fellow members and enthusiast.

I have a few questions about crossfire and sli.

My Setup atm.

Core i5 2500
Gigabyte ga-z68ma-d2h-b3
XFX-6950 1gb
12gb ddr3 1600 HyperX (4x2)(2x2)
1tb Seagate Hdd
750w Cooler Master GX Psu.

1. If i add a second 6950, say for example a 2gb version, does crossfire still work? and which ram will it utilize? the 1gb or 2gb?

2. My motherboard has secondary pci-e slot running at 8x, but i have a feeling adding a secondary card might interfere with the I/O ports, usb, and sound. I don't have a picture so ill post a link.

http://www.gigabyte.us/fileupload/product/2/3975/5084.j...

3. Or i should just wait for another year too see the options nvidia and amd will bring out?