I already went to the site after first buying the card and having the
same issue. It ended up that I got a driver for the card called fglrx,
which, after installing, I had to set as my driver through dpkg.
Unfortunately, after my upgrade to 8.04, Ubuntu's defaulted back to it's
included ATI driver - which is what gives me the resolution issue, and
I'm no longer able to choose a different driver through dpkg - all the
command "dpkg-reconfigure xserver-xorg" gives me now is a few options
about my keyboard and mouse, and nothing dealing with my monitor or
video card. So pretty much my issue isn't that I don't have the
necessary driver installed, it's that I can't tell my system to use the
proper driver. If there's another way of changing the driver, I should
be all set - I'm not too terribly concerned about 3D effects on this
system (half a gig of RAM and an 800mhz processor doesn't make it really
an eye-candy system, hence my preference for Fluxbox and XDM)