I am guessing the camera is in auto mode and is auto choosing the ISO for you.
That is the cause of the noise.
Reduce the ISO, and choose a lower f number if you can, your camera will probably do this automatically for you if you zoom out, take the picture, then use a photo editing software to crop the pic so your subject fills most of the frame.
with standard lenses, the f number increases the further you zoom, the f number is basically the eye of the camera, the bigger the number the smaller the eye, and so the camera's brain increases the ISO to get enough light into the picture to correctly expose it.
professional lenses have a constant aperture (f number) the whole way through their zoom range, but they are quite expensive.
I have just googled your camera, I see it has an aperture of f2.8 - f5.0. so when you are zoomed right out you'll have an f number of 2.8 which should cope with most of the dimmest of situations.
Regarding the saturation of the images, PC monitors display the pics differently to the one on your camera screen.
You can get monitor calibrators so you get the exact same image as the one on your camera display, but they are about £200 and not really worth it unless you do pro stuff.
If you plan on using Jessops to print your pics all the time, reduce the saturation in the camera settings.
If you print your own pics at home, just print some test copies and adjust the camera settings accordingly so they dont look washed out or over saturated. It wont give the professional results you would get with a monitor calibrator, but it is alot cheaper and the results should be pleasing.
hope that helps, any other questions just ask