Red hat Monitor Resolution

I have finally got linux to install on my machine although I had to give up
on Mandrake and burned a copy of Red hat. I can only seem to get my
resolution to waark at 1024x768 @ 16 bit. My vidoe card is an old S3 Virge
and the monitor is an old digital. I am only able to get X to run on a
manually enterd refresh rate at 1024 x 768. Any ideas on this.
Thanks,
John