How best to upgrade

I invested in my present set up years ago to play vinyl discs and as an afterthought added a cd player as vinyl lost favour. It was largely unused for many years as our children grew up, however recently I have re-discovered music (CDs) but feel my enjoyment is being curtailed by the lack of quality of 1 or more components. I want to upgrade but am not sure where to start, or indeed whether I would be better advised to discard everything and start again from scratch. Any help would be gratefully received.

My current CD set up consists of:

Creek Audio 4040 Amplifier
Monitor Audio R252 Speakers
Arcam Delta 70.2 CD Player