I would say no to all of them. You need to take the style up a notch. A sundress is a great idea if it is a nice sundress. The one you had from JC penny just looks a bit cheap. As for pref, strapless is not a great idea.Think dressy party with some sort of sleeve or one shoulder. Maybe something like this.
http://www1.macys.com/shop/product/j...%26slotId%3D91
Good luck!