Try a high boot
Boots have a definite autumnal appeal, whether paired with jeans or a skirt, or even a mini dress. If you're doing a lot of walking outdoors, they might be a little hot, but paired with a sleeveless shift dress, they might give you just enough "fall" to keep you satisfied. Something classic, like these Steve Madden 'Devoted' Boot, $172.99 at Heels.com, will be wearable for at least a couple of seasons.