German Citizenship for granddaughter of Austrian man

Hi everyone,

So here is my tricky family history:
Great grandfather = Austrian
Great grandmother = "Brazilian" but both parents from Germany

Their son (my grandfather) was born in Wien, Áustria while my grandmother and her older son were their meeting part of her husband's family.

My grandfather married a Brazilian woman whose grandfather was Italian.
They had 4 kids, my mother and three other sons.

All the have (or at least could have) Austrian passport just like their kids (my cousins) except for me and my brother.

The Austrian law says that all kids born from Brazilian mother, though daughter of Austrian name would only have the right to pass the Austrian citizenship if, by the time her kids were born, she was single.

The law though changed a bit and recognised kids under this same situation as long as they were born after 1983.

My brother and I were born in 1977 and 1981 respectively.

A bit unfair as the so called "blood line" doesn't make sense as blood is still the same no matter if born before or after 1983.

Is there ANY chance for me to get the German citizenship since Austrian until now, seems out of question?

Thank you very much, in advance for any help.