What you have read is true. But as the “2.4 Ghz wireless adapter” is built in, that is all you will need to connect the laptop to the internet. How do you currently connect your pc to your broadband modem? If it is by ethernet cable, then you are all set. If you connect via usb, then you will need to get a patch cable (the RJ45 is the connector on each end, like a slightly larger phone jack) to connect to the router.
HOWEVER, you could also add a wireless card to the pc itself. Taking my setup as an example, I have an NTL cable broadband modem connected to a Netgear WGR614 54 Mbps Wireless Router. These are both downstairs. My PC is upstairs and connects to the router with a Netgear WG311 Wireless PCI Adapter. My wife has a laptop with a wireless card and we can share the broadband connection and resources etc.