If you have notified the landlord of the mold problem, they did not deal with the problem and you can prove your children are sick due to the mold, then I would find an attorney.
Can I Sue My Landlord For Mold/mildew Damage And For My Kids Health?
Check your lease real quick to see if there is anything that waives your rights to anything like damages in cases where it's the landlords fault. I'm assuming the mold was a result of negligence or disrepair.