Help me dress myself?!

TQC, I have a ball/dinner in a few weeks, and the dress code is 'Black Tie'. My university is pretty lax with dress codes, so I bought something formal but not overly formal (I am shorter than the model, it hits my knees). My question is, what do I pair it with? It's winter, so I need a jacket/cardigan, but I have NO idea what to wear it with. Picture of the dress beneath the cut.





I will probably wear it with gold shoes and a gold bag. (Although black shoes are an option). I have short blonde hair.

EDIT: Is this dress just way too informal? Shall I take it back and get a floor length one?