Very sad. Unfortunate!
However, the situation is probably much different than you state. First and foremost: Most people with heart pacemakers live productive and active lives for many years once the pacemaker is installed. There is no need to whine about the stuff that Life has placed in your breakfast bowl. There are many persons born overseas of US Servicemen who have not found their fathers. Your story is one of the few stories with a happy ending. Do not complain. Count the blessing you have received.
Unfortunately, the State Department is correct in your case. Since your parents were not married, your father must have legitmated you or acknowledged before you were age 21 and you must establish a blood relationship [READ: DNA TEST] with your father, and demonstrate your father\'s US residence/physical presence prior to your birth. If his name is on your birth certificate, this is only the first step.
You do not mention the DNA test in your story. If a child showed up claiming to be my long lost child via an old girlfriend, FIRST I would want to verify the reality of the blood relationship. Unless I was too ill to care.
In order for a green card: you will probably still need a DNA test to document family relationship after all these years. The visa petition will be easier to get approved with positive DNA test results. Then, there will be a wait of either 3 years or 12 years for a visa.
Unfortunately your story is all too common from the 1960\'s.