I don't think you will have much luck. The nforce network driver needs to get compiled and you can only compile it for a specific kernel version. Simply adding the driver to a bootfloppy will be impossible if you don't have a rh 7.3 system at hand to use.
But their might be another good solution. I thought RH 7.3 supports install from a harddrive too. Not sure exactly how that will work. I guess you would have the tree RH 7.3 iso's and put them somewhere on your harddrive. Then the setup can use them.
For more info read: http://www.redhat.com/download/howto...oad.html#write