Alright, though we agreed to sponsor your flight as a caregiver for our kids, but why can't you apply for your visa the way Eva did? she got a normal work visa because i asked her how she got her visa to join my uncle in new Jersey and she told me about it, then I also consulted the U.S Immigration Service about hiring a caregiver worker into United States and they told us the same thing. You need a work visa and the process is described on the immigration website: http://travel.state.gov/content/visas/english/employment/temporary.html#howtoapply
Read it and you can also call or contact the U.S embassy in your country to ask about this information you got here.