Triple Monitor Questions

Hello, yet another post from me, got a few questions.
My rig is this:
Intel Core i5-3570k
8GB corsair vengeance ram
120GB intel 520 SSD
500GB hitachi 7200RPM
HIS HD7850
Sapphire HD7850
OCZ ZS750w

My question is, to run a triple monitor setup i was told one true displayport signal is required, and the card im using now has two mini displayport ports, one being used by a passive adapter, and the other monitor is just using a standard HDMI lead, and i know i need an active adapter for this to work. But the only ports on the monitors are HDMI and VGA and i don't want to use VGA. The only active mini displayport to HDMI adapter is this one http://www.amazon.co.uk/gp/product/B009BL2TY4/ref=s9_si... and i just want someone to verify this is what i need before i buy it. Thankyou.