The combination of Sassy & AngelDust is a fatal combination. The dress can be found on the lucky chair @ Sassy. The skin is one of the group gifts put out by AngelDust. The hair is a freebie on the Marketplace from Tameless.
Skin: Grace (Group Gift, Free) @ Angeldust http://slurl.com/secondlife/Jazz%20Island/151/197/22
Hair: Ellie (Free) by Tameless @ Marketplace https://marketplace.secondlife.com/p/FREE-Tameless-Ellie-Mega-Pack-short-hair/459495
Dress: **MESH** On Track (Lucky Board, 10 minutes) @ Sassy! http://slurl.com/secondlife/Sassy/59/57/34