Ubuntu - AMD FirePro - Resolution Problem

I have a fresh machine with a fresh install of Ubuntu Gnome.

I'm ruing a AMD FirePro w4100.

The only drivers available are compatible with xorg 1.10 so I can't use them I don't think.

The problem is that all my hardware is compatible with 2560x1440, but the max resolution I can get is 1920x1200.

I've attempted to cvt the resolution, add it through xrandr, and assign it to the output.

The option appears in Gnome, but when I select it the monitor goes black and loses signal.

I've tried it in different ranges of frequency but can't get it to work.

I'm not sure where to go from here, any help is appreciated.