Your definitely in need of longer exposures in a few of these pictures. Just set your camera on a tripod, and lower the shutter speed. (duh)
A lot can be done with brightness and color in photoshop. You can adjust the contrast, midtone contrast, brightness, shadows (lighten, darken), saturation, hue, everything. Photoshop can also help rid you of unwanted dust spots (usually on your lense) with the cloning feature. (so basically, the reason you have spots in your pictures is because there's dust on your lense.) If you have photoshop, you can look up tutorials on how to use the cloning feature.
If you give me permission to edit your last picture (to get rid of the spots) I'll show you how it's done.