If you connected the card while the computer is running you might search through dmesg to see what the card was called, or try to do an ifconfig -a to see if it shows up. If this is the only NIC card on the machine it will probably be eth0. In which case you will want to do a
only use eth0 if you know that is where your lan card is set too.
Here is how to set the card if with a static. Again check to see where your card is actaully defaulting too.
ifconfig eth0 [addr] netmask [netmask]
route add default gw [gateway]