Recompile the kernel to support your video interface with vesa framebuffer support. This requires reading (lots of it), patching the kernel and maybe writing some code to patch the kernel with. Start by reading the vesafb.txt file nornally found in the Documentation/fb directory of your kernel source.
Here I'll save you a bit of time;
There is no way to change the vesafb video mode and/or timings after
booting linux. If you are not happy with the 60 Hz refresh rate, you
have these options:
* configure and load the DOS-Tools for your the graphics board (if
available) and boot linux with loadlin.
* use a native driver (matroxfb/atyfb) instead if vesafb. If none
is available, write a new one!
* VBE 3.0 might work too. I have neither a gfx board with VBE 3.0
support nor the specs, so I have not checked this yet.