Okay, your pc has a USB adapter that you use to connect to a wireless hotspot. That's connection 1.
You have a wireless router, with one ethernet connection that you want to connect to a Wii.
First you have to get the Wii to connect to the wireless adapter. The ethernet cable from the adapter should be connected to your PC. (Connection 2)
With the Wii now connected to your PC (through the adapter and cable) bridging the two connections should connect your Wii to the internet.
This will only work if the hotspot is able to hand out multiple IP address to a single mac address ( from it's point of view your USB device will be requesting multiple IP address, 1 for the pc and another for the Wii) If the device won't give out additional address, you can try using ICS (internet connection sharing) which will give an IP address to the Wii and use Network Address Translation (NAT) to cross communicate between the two networks. I haven't seen a Wii so I don't know what kind of issues that might cause, but I know for Xbox live there's some port configuration that must be done to get the right traffic to pass between subnet when using ICS, and there some stuff (Media sharing to be specific) that just isn't supported with ICS.