I Successfully installed the catalyst (Fglrx) drivers, but now I found that I cant have a double monitor setup. I have two monitors:

1)Laptop Display
2)VGA Display (to 32" HDTV)

When I try to turn On my other display via Monitor Preferences I got this:

Would you like Screen Resolution to setup the virtual resolution for you? (Recommended)

If I click yes I will tell me to log off and and log in, but the second display doesn't turn On.

If I click no it says:
Your settings cannot be applied because the virtual resolution is not big enough to contain your screens.

I found out that by dragging the second display below the first it will turn the second display On, but I find that uncomfortable and when I try to maximize a window on the second display, it will maximize but not fully(a gap on the bottom of the screen)

Is there a way to fix this?