Help me see my kids again!!

I have not seen my children in 2 1/2 yrs.I lived in America close to 20 yrs, had to come to Brazil and cant go back.My mother passed away in a landslide and my father has been in the hospital for 2 yrs...I had to stay longer n Their dad will not send them and I cant get a visa...Im begging you to help me see them again,by granting me a visa to return to america.I have honored and served america for most of my life,see myself as american as any other born there and find it unjust I cant go back,specially my 2 sons being there! If you're a parent,you can nearly imagine what I feel,cant describe it any better then living ,dying inside each new day that comes....Once you become a mother,your children become part of you and to feel amputaded and helpless is the worse feeling one can feel...