I thought of some embroidery or applique too. Then the bonnet would be more 'dressed up' and the bright yellow wouldn't be the first thing you see.
You could do a pieced border with some of the yellow in it, to bring it together, but not all yellow.
It has an old fashioned appeal, don't scrap it, you have way too much precious time and lovely work into it.
I suggest a lighter flower on the bonnet, maybe a lavender?
Is that what that strip, or ribbon is in the sashing? I'd use a print though.
This top is way better than you think :wink: