Gala Apples

Can anyone help me please?   I think it may be to late in the year but never mind I have a apple tree in the back garden the type is (Gala) it is a very good cropper but this year its not looking to well the apples are small and as you can see by the photos not good at all if anyone can tell me what I need to do to get rid of the brown marks    the tree is seven years old.

It's scab I think  it's a fungus look here
http://www.ashridgetrees.co.uk/Apple-Scab

Thank  you mumofstig for the information.