Ah, both aren't working. You can download the package to a USB drive and transfer it over to your CentOS machine to install
Code:
su -c 'rpm -ivh packagename.rpm'
I'm not sure if it needs any dependencies, though.
And just to throw out there, CentOS is an Enterprise oriented distro, not really designed for netbooks. If you don't have a compelling reason to use it, you might consider switching to a more netbook friendly distro. The latest Ubuntu/Fedora/etc. should have the ethernet drivers available out of the box.