Agree with Cory. You aren't being told to send your contagious daughter back to school. Just that there is little value in taking Tamiflu and for Tamiflu to be prescribed to the rest of the family when the flu is out there and uncontainable now.
Obviously if her condition worsens, or she has secondary infections (i.e. ear infection, or whatever) then that will be treated. But the point of Tamiflu is mostly to limit the impact of flu on the very vulnerable (the list includes people with heart/lung issues for example, people who are immune-suppressed or pregnant as well). A healthy person is unlikely to die of swine flu, or rather, no more likely than if they caught "regular" flu.
Sympathies though - flu is grim. DD had full'blown seasonal flu before christmas and it was horrible for her. Took her an age to get over it properly too. DH, DS and I also got it, but in a much milder form.
SO basically, all you can do is nurse her, help her get better, practice good hand hygiene to try and not get it yourself (or other family members). And keep her off school until she is fully recovered. In the meantime, keep an eye on your other children to see if they get it, and then if they do, just repeat the above.