Hi Charles
Rather than trying to get a list of files to download, you could get your NIC working, then carry on with the normal installation. To get it working you would need to download only the files for the 'nforce-net' package, which is the following file:
http://212.219.247.11/sites/www.ibiblio.org/gentoo/distfiles/NVIDIA_nforce-1...
Place that in /usr/portage/distfiles when you've booted the LiveCD and do:
emerge nforce-net modprobe nvnet
This should install the drivers necessary for your network card and allow you to carry on with a normal install.
Hope this helps
Duncan Sample