I guess your mom would be your half-sister, but it's the closest I could get if we want her to be your grandma too while keeping blood-relation. I think managing to keep everyone being blood-related is good enough.

Hmm... trickier, but still possible.

So your mother makes love to her father and gives birth to a son. She then has a child with her son, which is you.

She is your mother as she directly gave birth to you.

She is your sister for being the sibling to your father, who is also your sibling.

She is your aunt for being your father's sister.

She is your grandmother for being the mother of your father.

It is.

So your father has a daughter with his mother and then has you with his daughter-sister, making your her your mother-sister-aunt. She then marries your grandpa, becoming your grandma now too.