Multi display set up

Hi there. I have a mac pro 2.5GHZ 6 Cotr intel Xeon E5 16GB memory with AMD FirePro D500 3 GM graphics card.

I'm trying to run 3 screens set up.

I have Wacom centiq 24" HD display, Apple Cinema display (older version but run on DVI via thunderbolt vconvertor) and wanna add up an HDMI Sony TV as a playback screen.

What do I need to get or what will work for this set up? Apple computers are only supporting of 2 screens. How can I add the 3rd? I only need it for playback.

Thanks

Dana

Nothing works for me. PLEASE HELP!