Hi Sophie and Nate
I am also in the same position as you, well maybe 2 weeks behind. My medical is done and packet 3 sent and I called the embassy in London today to see if they received my packet 3. The nice man on the phone said it takes them 2-4 weeks to process the DS-230 Part 1 etc etc and I should call back then and he would be able to TELL ME THE INTERVIEW DATE OVER THE PHONE!!! Therefore, seems like you should be calling them round about now! beats waiting for the postman :-)
Find their number here,
have have you case number handy.
With Regards to your interview and photos, no harm in taking some. I sent photos of me with my finaces family and him with mine etc as proof of our continual relationship. I have also read alot on line that you should take copies of everything you have ever submitted to them to the interview, like all you I-129f forms etc etc, as there has been reports that certain forms have been "mislayed" and if your able to produce them there and then, then it can only go in your favour. Therefore, whilst you wait for your interview date, wont hurt to get you finace to resign (if you didnt take photocopies of the original) forms which required his signatures and post them over to you.
Good Luck!!!!! I know how you feel, this final hurdle is the worst :-(