That looks just like what I'm wearing today!!http://www.craftster.org/forum/index.php?topic=133816.msg1310208#msg1310208
It's a mild 50 something degrees fahrenheit here and I've got it paired with thick tights and little ankle booties. You should definitely keep it a dress and wear it year round! Another option would be wearing the dress w/ skinny jeans and flats. The key to pulling it off is since it is a dress, keep the legs accentuated so you're not swamped in a bunch of fabric. Hope this helps you transfer the dress into winter wear!