What can I add to the dress below so I don't feel too cold?

kimono jacket, plain coloured knit jacket, shawl.

Anything really because this is a casual dress it can match anything as long as it's not too fancy. Better keeping things simple and clean and don't wear a jacket that's too long because it may kill the dress and not allow it stand out like it is supposed to and don't wear a jacket that is over the waistline because it can make it look awkward and give an illusion of flat chest and a wider waist.

I would personally go with something loose like a kimono since it can blend in with the fabric and the pattern of the dress and make it look like it was made in a set. A knit jacket can give a more ladylike and sophisticated look.

a shawl can help warm you up but it won't really look nice unless you get a very sophisticated looking one or else it can give you the hippie look....unless you like the hippie look. But really best go for the kimono

it's an elegant dress, I would ditch the hoodie and go more for a cardigan. you could add a scarf to keep you warm, and definitely wear boots weather permitting

I would add a lovely faux fur coat, some elegant boots and a warm, vintage cloche.