For situation 1) you'll want less than 30-sec. if you want to avoid star trails:
Our first night, the stars were bright. by
dcstep, on Flickr
For situation 2), pump up the ISO to around 6400 and be sure to hold the camera steady. Perhaps the reason you're not seeing an aperture is that it's impossible for the lens that you have on. The camera is calculating f/1 and your lens only goes to f/4. Pumping up ISO will solve this:
King's Arms Tavern - Colonial Williamsburg by
dcstep, on Flickr
Click on the images to go to Flickr and see EXIF data.