Welcome, Ms. Beacon!
Please, for the good of the children, have them evaluated by appropriately-trained and licensed mental-health professionals. While your assumptions may be correct, they may just as easily be incorrect. Only one of the aforementioned professionals can make an official diagnosis and advise you on the proper follow-up care.
We're just a bunch of ordinary people, many with some form of Autistic Spectrum Disorder (and many without), and none of us (to the best of my knowledge) has the right qualifications to advise you in such a critical endeavor as raising children - especially children with special needs.
Besides, once an official diagnosis is made, you may be able to receive some sort of public assistance for the children's care - this alone is worth having them evaluated by appropriately-trained and licensed mental-health professionals.
Again, welcome aboard!
-Fnord-