Get back my memory on a 4gb

I have a Nano clone 4gb and I had an extra drive when I plugged the usb in. I used the Rdisk tool to take that other drive off and now windows is telling me the player is only 235mb. I know that my drive is not really 4gb but I want atleast more space then 235mb. Could someone tell me what I would need to do to fix it or get more space.

Thanks,
Mukieluk