I think it is a lovely quilt. I see the symbol that you see, but in this beautiful quilt I don't feel that it has any bad connotations. However, if it bothers you, then it needs to be taken apart. I've surgically fixed one block by removing the stitches all around and reinserting it (when the block was turned wrong), but when there are several to fix it might be easier just to do them all at once by taking the whole thing apart.
However... why not wait a few days, think about it, and see if it still bothers you? I think you've made something beautiful that can destroy the power of that symbol, at least for you, if you let it. There are many beautiful old quilts that intentionally used the swastika design, before it became associated with the Nazis. It's not clear from your post whether your mother is still living, or whether the quilt is intended for her. If it is indeed going to her, you might ask her opinion.