an Ethernet network adapter for your PC.
Then connect the modem to one of the PC's USB ports and the PC's network adapter to the Ethernet port on the wireless access point. Set up the access point software via the PC.
The access point will now broadcast the broadband connection to the Laptop's wireless network adapter.
An alternative (and perhaps better) solution might have been to buy a wireless router. Then you could have connected the broadband modem direct to the router, and broadcast the connection wirelessly to both the PC and the laptop. The advantage of this method is that you wouldn't need the PC to be on if you just wanted to use the broadband connection on the laptop.