You have a total of 8 GB, which is a lot. That should get you nearly 2,000 pictures. Your camera has nine megapixels, which is far more than you need. If you decrease the resolution, you should be able to get even more images. If you're smart about your picture-taking, don't take a lot of duplicate images, don't take pictures of things that you won't care about later, and delete bad images (poor focus, poor exposure), you shouldn't have a problem. With digital, I find that people are taking more "garbage" shots. People were a lot more considerate about the shots they took in the days of film...I miss that (especially when people insist on sharing their vacation photos with me). If you don't think 2000 images is a lot, think of this this way: that's about 83 rolls of 24-exposure film! Would you have brought 83 rolls of film with you back when you had a 35mm camera?
If you want to play it safe you can buy extra memory cards and leave them in their original packaging at the hotel. Only open one at a time, and only if you need them. After your trip, return any unused cards to the store.