A tale of two networks

So I am volunteering at a school in the arctic. Trying to work on their network and I have run into a problem, here is the setup. The main network is working fine, all computers are online and can see each other. The school just bought some new laptops and they are wireless so they got a wireless router. The laptops can connect to the Internet and can see each other but they can not see the existing network. What they want to happen is for the laptops to be able to print to the network printers and for them to be able to file share with the existing computers. The wireless router they are using is a linksys WRT54G (linksys link) I can not think about any other information you may need but just ask and I can find it out for you

thanks in advance
Craig

How are the two networks connected? Are you using IP addresses from the same subnet for both networks?

And I'm a little confused about your situation. Is this correct? You have a wireless router which connects to the Internet. Laptops connect to this wirelessly. You also have computers on a main network, connected together using a switch/hub. This switch/hub is then connected to a standard port on the back of the wireless router.