You may want to just get a single great card instead of two low-mid range cards. the HD7870 is right at your budget and supports up to 3 monitors (if you have a display port monitor), with the added benefit of Eyefinity. It also has more G-RAM for your displays than two 560's could bring. http://www.msy.com.au/product.jsp?productId=8937
Dont understand why you need 16Gb unless your video editing, but anyway, the RAM you picked should be fine.
perfect, I was literally just about to edit to say that a HD7870 was another possibility, and all of those prices are form msy, the only thing is that htey are out of stock of HD7870s so I'm thinking of heading over to IJK for the 7870.
my only question is about the different display ports meaning a different quality picture, I saw another thread on here and have heard a couple of times about using the mini display/HDMI/Dvi results in different brightness/colour on the displays.