Wireless broadband does not use a modem. Wireless broadband uses a wireless NIC plugged into the PC.
What ports does the Wii have?
Does your laptop have an Ethernet port (NIC)? If it has an Ethernet port and the Wii also, look up ICS (Internet Connection Sharing). Be prepared for problems, trouble shooting, crossover cables, general headaches, more trouble shooting.
For a trouble free setup, get a real cable or FIoS connection, a modem, and a wireless router. Connect the Wii to the router.
I have Verizon wireless broadband, using a USB modem supplied by Verizon. Is there any way to connect my Wii to the internet??