Depending on what you want to capture on your vacation, you might not need another camera. However, I would recommend you get a cheap Canon point and shoot and hack it with CHDK, which basically gives you full control over everything about the camera (and you can do time lapses with it, and even play games if you are so inclined to modify it that way!). Buy it now (make sure the model is compatible with CHDK) so you have time to learn CHDK before you go on vacation.
I just got back from Costa Rica and only had my GoPro. The only time I had wished I still had my (now sold) Nikon D80 was when I wanted to take pictures of the wild life, and any point and shoot could have sufficed in that situation. Instead I got creative and still found ways to capture the wildlife. Home-made trekking GoPole for $15 works wonders, as does luring iguanas right up to the camera with pieces of Chicken
I recommend against the Nikon 1 because of the great points made
here. Interchangeable lenses on a point and shoot, DSLR hybrid camera are enticing but its sort of like investing in Mega Blocks when Legos are such a better product with really great licensing. There are so many great lenses (made by Nikon's lens company and outside companies) for DSLRs that wont work on the Nikon 1, and the lenses that are for the Nikon 1 have no chance of being as great as ones you could get for a true DSLR. Skip the 1, buy a used D90 or D5000 and a couple of great lenses. You will even end up cheaper than the 1 and have a better camera. OR, save about a thousand dollars and just get a point and shoot!