Complicated family case, Advice if possible

In April 2004, my step-father died unexpectedly. He was 41. My mother and I are UK nationals are were I the process of waiting for our green cards. At that time in the process, the only thing left to do was the medicals and the interviews. My mother informed immigration of my step-dads death right away as to not hold anything back. We received notice to go get medicals and we did. Then we received the letter for our interview for Nov 2004. At this time, my mom and step-dad had a 14 yr old son and a 12 yr old daughter(US citizens like step-dad) and myself, 23 at the time, had a 2 yr old US citizen son. We did everything we were asked all along in the filing of forms, or I should say my step-dad did. So we were not expecting any problems as they were notified of his death right away. In Nov 2004 we went to out interview to be told within minutes: we should not even be in the country any longer, if my step-dad had committed suicide we would have a case (only 7 months after the sudden death), my brother, sister and son could stay even though none of them had any other parents or family to live with. Because we were told to leave we did in Dec 2004, just over a month later.
We have since been told my mom could have refiled as a widow for us. After we had left the country. We were banned for 10 yrs for illegally overstaying for one day. That time is now up. And now we can't seem to find the right way to get back. PLEASE give any advice possible.