First, you cannot use the USB connection on the VM modem at all. Virgin Media do not recommend it anyway and it won't work with a router. And no, you can't buy a router that will work via USB and you can't connect your PC to the USB port and the router to the ethernet port, that won't work either.

You first need to power down the VM modem, the router and the PC. By that I mean remove the power leads from all of them. Next, leave the Virgin modem connected to the Virgin cable port where it comes into the house and then connect the modem to the router using an ethernet cable (colour is immaterial). As your PC hasn't got an ethernet port you will need to buy one of these and install it in your PC. Once you've done that you can connect the router to your PC and then power up the modem first. Wait a couple of minutes then power up the router and then finally the PC. The ethernet card will install itself and you will be automatically connected to the net. You will need to uninstall the dial-up connection associated with the old VM USB installation.

Finally you can then log on to the router and set up your wireless security before your daughter connects to the router via wireless.