Problem with resolution on Radeon HD 7459 card (Squeeze)

[Han Soo Chang <hansoo77jp@gmail.com>]

Hi, I recently installed debain squeeze on Hewlet Packard Pavillion
h8-1280jp, which has a ATI Radeon HD 7450 graphic card.
However, the resolution of the monitor is limited to 1280 x 1024, and
I cannot get any higher resolution.

I have xserver-xorg-video-ati, xserver-xorg-video-radeon, and
xserver-xorg-video-radeonhd installed.

$lspci | grep VGA
01:00.0 VGA compatible controller: ATI Technologies Inc Device 677b

is the response to lspci.

I checked the log file /var/log/Xorg.0.log, and
it seems that the system does not recognize my graphic card, and fall
back on vesa driver.

I would like to ask what is the best option I should take?

Should I install a newer kernel from the backports?
Should I try propriety driver? But using it makes me a little bit
nervous, because I fear that it might cause some trouble in the
future.

I have no experience of building a kernel, and I would like to avoid
it if possible.
I would like to have a stable system that I can rely on.

I would appreciate any suggestion to improve this situation.

Thank you.

Han Soo