Running 4 monitors off a single graphics card is, I believe, impossible. The reason being is that there are only 3 electronic headers present on the graphics card itself which serve all ports. From my experience of doing a triple monitor configuration using the display port is the way to go and it looks to be the same for yours. See http://www.tomshardware.co.uk/forum/349967-33-radeon-77...
It tells you right in your very own link it only supports 3, so, well, ummmm, not sure what we're supposed to make 4 work.
Ok well I'm now trying to get just 3 of them working for now but I'm struggling to get even the 3rd display working,
Iv got the 2 HDMI monitors working, one using the HDMI port and the other using the DVI to HDMI adapter that was in the box and now the 3rd monitor is the monitor with the DVI/VGA ports on it,
for this monitor I can't seem to get it working using another DVI to VGA adapter on the second DVI port of the card.
Will I need to get an Display port to DVI adapter or a Display port to VGA adapter and if so will I need a Active or passive Display port adapter for this monitor?
There's a recommended one in the thread I linked so I would use that. To be certain it will work, use an active one, if you want to use a passive one check the interwebs and see what other people have used. Also this post has a lot of useful info on them: http://www.overclock.net/t/721931/active-vs-passive-dis...
As I understand it, 2 of the hardware headers are split across the HDMI and DVI ports and 1 is used for the display port. This means that you can run 2 monitors from any configuration of HDMI and DVI and 1 monitor form the Display Port.