I wouldn't go for either pair of jeans. The smaller pair look a bit neat for the style they look like they're supposed to be, and they're a bit short. The bigger pair are too big, so I think your best bet is a different pair altogether.
The dress is fine, in the nicest possible way; I imagine there are lots of dresses out there that would have the wow factor on you, but I appreciate you're short of time. If last year's dress is gorgeous, wear that. If not, the one in the photo is perfectly inoffensive and appropriate.