I found this on JKK Mobile. All you have to do to allow Wifi while tethered to your PC is to download the config file found in Advance tab when logged into the router using
http://192.168.1.1 while in Wifi mode. I also found that Fire Fox is not friendly with the router address. Use IE for logging into the Mifi router. Download the config file to your desktop. Open up notepad and drag and drop the config file into notepad and look for this string <routeroverusb>0</routeroverusb> and change the 0 in the middle to a 1 like this <routeroverusb>1</routeroverusb>. Now save it and go back to the download page on the advance tab and browse for the file you just edited and saved and then click upload. After it loads just log out and now you can charge and have Wifi while tethered. Let me know if you have problems with this. It worked like a charm for me.