Need to Upgrade to 1000mbps Lan Connection

[satyamy]

My friend has a 7-8 different PC's in his office all are connected to a switch of 100mbps & a Grey Color CAT Lan Wire
He need speed
So he need to upgrade to 1000mbps LAN Connection
I want to know what does all he needs to do this

His PC's Config is
Intel P4 (2.8 & 3.0), Intel 845, 865 & 102DC Board, 512 & 1GB RAM, 80-160GB HDD, 17" CRT & LCD Monitor & onboard LAN

Pls can you tell me what hardware he need to upgrade to 1GB Lan Connection & what will be its cost...........?

[The Unknown]

I don't know the cost but i think an addtional Gb LAN Card would be needed. Standard Lan cards are 10/100. Most mobos have 10/100.