Low Res only on 30" cinema display on new MacBookPro

For some years I have been using a 30" screen on a MacPro but the MacPro is faulty so last week while I was visiting Hong Kong I went to the Apple Store to get their advice . They said the new MacBookPro can use the 30" display at the 2,500 x ?? resolution the same as the MacPro.

So based on their advice I bought a new 13" MacBookPro with retina display and the twin mini DVI adaptor cable they recommended to connect the screen to one of the thunderbolt ports.

When I got back to the Philippines I connected the 30" screen to the MacBookPro but The maximum resolution setting I can find is only 1500 x 800.

This is extremely ugly and near useless.

Can anyone please advise what I can do? Is there software for the 30" screen I need to install or something?