Ok. As you may already know, the nvidia drivers have two components: the kernel driver and the GLX driver (OpenGL).
The GLX is the same for all architectures:
There are various flavors for the kernel driver, depending on you architecture:
Intel (i686) one processor:
AMD one processor:
If you have more than one processor and/or more than 4GB RAM, you will need different rpms. Look for them here:
In general, you must look for the plain vanilla Red Hat 7.3 driver (without upgrades).
Now, I always recommend people to use the tar files, since they should work on all distros and architectures. But, in order to make them work, you need the kernel-source (the exact same version of your current kernel) and the make libraries.