Your best option is to buy an ADSL modem that has an ethernet connection. There are loads available, you can even buy wireless routers with the modem built in. Your other option is to connect your USB modem to your PC and your router to your ethernet card and enable internet connection sharing. This should provide an internet connection to the router which in turn will provide wireless access to others. The only downside to this is you need to have your PC turned on for anyone to access the net.