2 22inch screen, yet not able to have a large resolution, help!

[Rainagul]

Hey.

Well currently I have two 22 inch Samsung monitors (1680 by 1050) sitting next to each other that are plugged into my XFX 4890 XXX.
I was under the impression that I would be able to run a resolution of 3360 by 1050.
However, using my CCC I am able to position the monitors in the way I want them (side by side), but I only have the options of either "Extending" or "Duplicating" the monitors, there is nothing that I can see that would either merge, or stretch the monitors to get my desired resoltion.

Anyone have any solutions for me?

 

[Rainagul]

Thanks for the quick replies.
I mainly wanted the large resolution, so I could have a larger area to work in with my video editing software (since spreading the interface over 2 screens at 1680 by 1050 looks wierd), but I also wanted it so I could try larger resolution gaming, but it seems then that I need a 5850