Figgi,
As Srobarts says, you can do a lot to improve these shots. First, can you set your camera to take pictures in RAW? I don't know your particular camera, but if it does, set it to take JPEG and RAW shots at the same time. It will take one of each automatically without you doing anything else. If it takes RAW shots, it will also have come with some software which you can use to manipulate the shots (brighten, sharpen, change contrast etc.). It will probably have some kind of software to manipulate your existing shots anyway, even if you can't take RAW shots.
If you really want to go mad and can afford it, Photoshop 'Elements' (£65.00 from Comet, Dixons etc.) will allow you to do things with your photos you won't believe possible until you try it!