I think you just need to "dark it down" for Fall......stay away from bright colored tights, etc....those kinda scream Spring\Summer.
When I look at this dress...I see bright colors and texture (with the lace at the bottom)
If I were given this dress and had to style it to wear in the Fall, I would personally add polka dots!! The lace is pretty and feminine, and there is something about polka dots that is so whimsical to me and fun.....so Id wear it with a polka dot bolero jacket, something like this:
I understand your reader also wanted a sweater or scarf, and since the bolero jacket is long sleeve, Id go with a scarf. I love the feature of the lace on the dress...its fun texture, so Id add a bit more texture by adding this really sweet scarf...it has a slip hole, where the other piece of the scarf slides through:)
My first reaction was to style it with brown and/or orange since they (like yellow) are the color of fall leaves. I am thinking of maybe a relaxed/slouchy brown cardigan and brown tights. The bag you are carrying in #2 is perfect for what I have in mind.
here are some other ideas for Fall stylings for this dress. I think layering is key and layering with Fall-like colors. Yellow is a color of leaves in fall, so you can think about what types of colors you tend to see around yellow in fall. Anyway, I put together a polyvore with some ideas for several different layering and accessorizing outfits for fall.