As you increase iso you will get a drop in quality, you will have to decide where it matters in your pictures, newer (and top of range) cameras are better at this, I would expect 800 to be unnoticeable, 1600 just starting to see changes and so on. You have to play, it will help.
Perhaps you can adjust the colour to be a bit more vibrant, if you can get titchfield to look like california if you like
. It will get better/easier on sunny days, indoors is almost impossible.