If your card is assigned eth0 then do this...
try dhcp first..
if you do not have dhclient try this..
Verify the configuration with this...
If that fails to work you can manually configure the interface like this..
ifconfig eth0 192.168.1.101
Use the ipaddress you should have for the machine.
Now you need to add the nameservers to /etc/resolv.conf
#contents of file /etc/resolv.conf
Use the correct nameservers for your connection.
Now you need to set a default route to your gateway
route add default gw 192.168.1.1
Use the ipaddress of your gateway router.