You can contact private guide tours that offer personalizaed (night) tours, probably starting Downtown by car and then Miraflores and Barranco).
awardticket had a similar question last month, there are some suggestions at this thread:
11 hours at Lima
I support the idea of Miraflores and Barranco, it's more friendly for walkers than downtown Lima (I mean night tours). Plenty of restaurants too. Now for the 1am-4am time.. it depends on what you like (still walking? dance clubs? peņa/folk shows?)