I ended up going to the bookstore that was in the movie theater complex and getting a great Lima map (it shows the block number so I can find practically anything!) and a book of Peruvian myths and legends in Spanish. I still had a ton of time so I got some helado de lucuma, or lucuma ice cream, which I have never found outside Peru. It's got a unique flavor that I like!
The movie was of course great. I hadn't re-read the sixth book before seeing it, so I couldn't pick up right away what things were missing, aside from a couple memories of Tom Riddle, some quidditch, and a major fight scene in the end in which a character gets hurt and it plays a role in the seventh book. It demonstrates how the Weasly family has sacrificed for the overall story, but they also added a scene that showed the Weasly house burning down, which had the same effect. The scene in which everyone raised their lit wand near the end was also different than the book, and I thought better. They also had an annoyingly high number of scenes that demonstrated teen angsty love. I didn't remember it being so annoying in the book... Overall, it was a good night and I had fun, even though I was by myself :-)