Section 245(i) may apply to you, so that you can eventually adjust status. It depends upon whether you can prove that you qualify. Your B1/B2 visa expired when your I-94 entry card expired for the purposes of staying in the U.S. The visa expiration only allows the visa to be used for entries and exits during the period of validity, not to stay for a full ten years.
Your fourth preference family visa may not be ready for use. If you file too early, then you can lose a lot of money and can even get a deportion order as a result.
A very experienced immigration attorney should go through all of the facts. There may be eventual hope for your children over 21 years old, but this is unclear without further investigation.
The above is general information and is not meant to create an attorney-client relationship.