Yes you can access files on both the usb drive and the windows drive. The easiest solution would be to open a file manager and just go to them. What distro are you using ? I use puppy linux on a usb stick, then I can just click on an icon called "drives" if I remember correctly, it offers the option to mount them, (which if it isn't happening automatically then you need to manually mount them), then it uses a file browser, I never really noticed which one(might be rox-filer), and I have access to both other files on the usb stick, and any local files on the pc I'm using. I've never used QEMU though, so I'm not sure what it's capable of.
But first, we need to know what distro and maybe what desktop you are using. Have you rebooted into a linux only environment ? Or is windows still on, and you are using linux in a VM ? The more info the better....