My sympathies. We had multiple lice incidents when the kids were little(separated by years so not reinfestation).
The best advice I got was to not go crazy with laundry and vacuuming. Launder their bedsheets, hats, lovies and vaccuum after the initial infestation but you don't have to keep repeating it over and over. Lice don't live long off the human body and the nits won't hatch except at body temp:
http://www.cdc.gov/parasites/l.....event.html
But it's important to get rid of the nits, and many lice have become resistant to pesticides. So after the initial Rid treatment, we sat down every 3 days an methodically combed through my DD's long hair, pinning up the strands and going through with a nit comb. I used mayonaise which is supposed to smother the lice (may be a myth), but also "unglues" the nits. Eventually when there were no nits, I went to once a week, and then a monthly check.
It took a long time, but we put on a video and watched it after dinner while we combed.
Good luck!