With your height, weight, and long legs, you will look fabulous in just about anything you choose! Try TJ Formal (they've been in business since 1969 and online since 1997): – they have all sorts of dresses and once you choose a department, you can put in your filters (on the left) you list above to narrow down your choices.

Specifically you might try looking at La Femme dresses – most are gorgeous and sophisticated:

Here's a few you might like:

Good luck – hope you find something you love!