you need to connect your comuter to the router as well - if it has an extra port, just plug in to this.
If it does not (then you have a very bad router or your mistaking the router for a modem or something else) going on idea that it is a router with 1 port, you will need a network hub - this connectes to the router instead of your dads PC and then both urs and his connect to the hub. For the price of a network hub you could probably get a reasonable quality router for same price
Make sure you use a switch and not a hub. Hubs will slow your network speed down. A switch is much better on a network. I am sure vibe meant a switch.
Pretty much all SOHO (small office home office) routers come with a 4 or 5 port switch built into them.