Hi! welcome to LQ.
one thing that might be the cause of the problem is the RedHat 4. (it's ancient!) I would definitly suggest you trying a different and newer distro, such as fedora. Or, try a one CD distro if bandwidth is a problem- ubuntu, mepis etc. If bandwidth is a REAL pain, then try ubuntu's shipit feature- they will ship free CD's to anywhere in the world for free- they will even pay for the shipping. (http://shipit.ubuntulinux.org/
ok. If you must persist with the older distro, my question would be to check out the capabilities of your monitor (google) is it capable of a high resolution? (nevermind if it did it, what does the product's website say?) umm... you will need to look in /etc/X11 to see if there is a configuration file- for me on slackware it was /etc/X11/xorg.conf and on debian it was /etc/X11/XF86Config-4
look for a configuration file that is either xorg (unlikely) or Xfree86. (x.org is a fork of xfree86)
hope this helps.