SATA 3 support is not available on LGA775 motherboard! The board you are looking at is LGA1155 and does not fit your LGA775 CPU. A cheap solution would be an add in card http://www.newegg.com/Product/Product.aspx?Item=N82E168... will not reach full SATA 6GB speed since it is limited by PCIe x1 interface yet faster than SATAII.
I would though not worry about it and get the SSD and run it on the SATA 3GB that you already have! Very little gain from anything else!