Well after looking at the web page of the link you provided I cae accross the box size and the box size that the card comes in is 12" long ,6" wide and 2" deep. since the card is a 2 slot card it should be just under 2" thick and the card has to be just under 12" lomg and less than 6" wide. So the spot you want to put the card has to have 2 slots worth of space anyway.
should be around 7-8 inches long. Maybe even shorter... but these medium end cards tend to not be long. Most middle range gaming cards usually is 8-10 inches these days unlike the GT2XX and HD4xxx which came in 9-12 inches or more most of the time.