New CPU and GPU you might as well get a new computer to be honest. Alright so depending on what new chip you get it could not work on your old mouthed board depending on the model, type, year it was made so that would be the first thing you should look in to. When you get a new motherboard then you probably should upgrade your ram. It's kinda like that song with the bones my something like "my foot bone is connect to my leg bone" anyways just save an extra £2/300 on top of what you're spending on a CPU/GPU and get everything else new.
Edit:
Fredd wrote:
an amd fx of any kind is really good (Just for gaming though)
If you are gonna use your pc for other stuff than gaming you should get an i7
Me, Chute and EMP found our boii Jazzie one for like a £100 more than that and it was complete and already built.