Ok, you have a small aperture (number you'll see with 'F' in front of it) range so you definitely want to take advantage of the ISO setting. Hopefully I can give you a really simple aperture/iso tut here quickly: the aperture setting controls how wide or narrow the opening of the lens gets. Wide open means more light getting in. Other than light vs. dark the main difference between a high and low aperture setting is depth of field, which is the effect of having things close to the camera in focus and things further away out of focus, or vice versa. The smaller the aperture, the better (or simply deeper) the depth-of-field. The problem with a smaller aperture is less light getting into the camera, but that's where ISO comes in. ISO basically determines how sensitive the sensor in the camera is to light coming in. So if you want a better d-o-f you drop the aperture and raise the ISO to a higher setting b/c ISO doesn't effect d-o-f. So say you want to take a picture of a tree sitting by itself with mountains in the background and you want the tree in focus with the mountains a little out of focus so the tree pops. Drop the aperture (also called F-stop) to 3.5, raise the ISO to 800 (or 1200 or 1600), and take the shot.

Once you get the light control down, you can work on the shutter speed to really tweak things, and ISO comes into play then too. Most people can't hold a camera still enough to take a shot any slower than 1/100th of a second. You can sometimes get away with 1/80 or 1/60 with a good camera, but typically you don't want to go under 1/100. The problem is 1/100 and faster don't always let enough light in, but again you can tweak it with ISO.

I don't know what settings your camera has, but look for an aperture priority or shutter speed priority setting that'll let you work on specific areas. Again, you want to get to the point you're doing all the work manually. Nature isn't a person. It doesn't always behave the way you want it to and it rarely ever sits still and once you've missed a shot it's unlikely you'll be able to get it back.