You should receive child support from the County as an extended relative.
You do not want "cash" assistance. You want child support for Fosterchildren.
Call up the Worker, and ask why you are not getting child support.
If the Worker tells you that you will be getting the money, then it is a problem with the paperwork.
Go to the DCFS Website, and look up Fosterparent support, and contact the County from that site.
Sometimes (many times) there is a long delay in receiving support.
Good luck to you.
Please note that this answer does not constitute legal advice, and should not be relied on, as each situation is fact specific, and it is not possible to evaluate a legal problem without a comprehensive consultation and review of all the facts and court pleadings filed in the case. This answer does not create an attorney-client relationship
The state also has a Kinship Guardianship Assistance Payment program for relatives receiving children from Delinquency or Dependency Court. More information can be found at http://www.childsworld.ca.gov/pg1354.htm . This may be helpful if the children's parents are unwilling or unable to pay child support and Social Services doesn't qualify the household for cash aid. Be sure to read the eligibility requirements, though.