Thanks juanito 
 
 
 i could change the resolution 
i am still working inside virtual box, 
How can i make the /etc/X11/xorg.conf file to be persistent?
when i unpack the Xorg.7.4.tcz , i could find the xorg.conf.vesa but not just xorg.conf.
could any one please tell how will the xorg.conf file be created in filesystem from the Xorg.tcz contents?