Theres no specil order of the cards you get them like this:

Exterminator's cards:
Shellshock: Get all weapons and Omega mods.
Eviserator: Get over 100 Max Nanotech.
Ace Hardlight: Get 4,000,000 Dread points.
Reactor: Buy all the Mega weapon versions, including the Harbringer.
Vox: Get all skill points.
Vox's pet: Complete all missions under the highest difficulty setting.

Are you sure that you have to get 4,000,000 dread points for ace hardlight cause i have have him and i only have about 500,000 dread points