1. Get the computer out of the bedroom.
2. You can limit the time of use via configuring wireless router or unplug the router as others have said, but her lack of rule-following is becoming your headache. is that fair? so ...
3. Tell her the rules, expect her to follow them, and show her that violations will cause her to lose her computer and you dont want it to come to this:
Thst. Was. AWESOME!