Wacom Cintiq 13HD, simple connecting question!

I've got a 2009 iMac (mini display port but not thunderport). I'm about to purchase a Wacom Cintiq 13HD (pen not touch). All I want to know is exactly which adapter I need to buy...I've searched several times and seem to get about four different answers!! Is it a mini display to HDMI...or VGA...or DVI? excuse the ignorant question but any help would be great! Plus, these cables, are they long enough to reach from the mac to the tablet still allowing me room to move the table around?

many thanks!

Nigel