Please help in configuring LAN cards to access internet..

Can anybody help regarding this issue..

Well we have taken lease line connection for internet and BSNL gave these Usable WAN IP address range - to 70 (total - a subnet of
DNS address -
Gateway -

We set these addresses on the router IP - (on fast ethernet)accordingly with given DNS and Gateway, it is working fine

PC's are connected to Switch (24 port - unmanaged) which in turn is connected to the Router

On PC's (all using XP sp2) we set the given addresses as
For Four PC's
IP - to 70
DNS address -
Default Gateway -

If we are adding 4-8 or more than that no. of PC's how to connect them also so that they can also use the internet..

Can we do this by adding one more LAN card to one of the PC and make this as a server (initially there is no server or PC as a server). If so, then how And What IP addresses (plus DNS and gateway) i have to assign to 1st LAN card and what to the 2nd LAN card. What IP address (plus DNS and gateway) should I assign to additional PC's.

Is there any other procedure also to use. If yes, then please do tell me about that also.

Please help me out giving details.
Thanks in advance