you will have to connect to internet, see what updates are there for your nvidia card & download them.
Although I have not used sabayon hence cannot say but if you have Gnome 2.18 and are on broadband router+modem or modem or just ethernet it is very easy. Go to System > Administration > Network although it makes sense if you have plugged in your modem/router or ethernet connection while installing. But anyways, it will show 2 wired connections, if you had ethernet or usb connected or whichever you connected that should show up as the first connection. In my case eth0 (eth = ethernet) . Click on Properties will show you Roaming mode, un-check that , put static IP Address of your router something like
IP Address 192.168.1.2
Subnet Mask 255.255.255.0
Gateway Address 192.168.1.1 ,
A simple way to find the correct values of your system is if you are on dual-boot then give ipconfig /all or just ipconfig either way you should get the values . Then go on to DNS Servers and give the DNS servers of your ISP providers or any other DNS provider. Make sure tht ipv6 is disabled atleast in firefox in the URL give about:config and when the filter is there, just give ipv6 the entry which comes up, just double-click it.
If everything went smoothly, try pinging your DNS server for starters something like :-
ping -c5 61.1.96.69 (this is one of the BSNL DNS server IP Address). In case if it is Airtel or some other ISP provider call them up and ask them for your DNS Server IP Address and enter them there. There would be 2, a preferred one and an alternate one. Give both.
if the ping is successful then try pinging something without the nos. like
ping -c5
Google
If this also comes good go to your browser and enjoy the Net. As far as updates are concerned, there should be some kind of Graphical update-manager in the System > Administration thing. Download stuff, look in forums, edit the repositories and in no time you will be a linux guru.
There is lot of excitement atm as X.org 7.3 is near completion, suffice to say very very interesting times ahead