Hi Sam
First I cropped away the bit of wall on the left. I was going to leave the blank canvas but I tried a square crop and thought it looked quite good.
Then I used Unsharp mask: level 20, Amount 20. Which often seems to give an image more clarity.
Then I adjusted the levels to make the colours a little deeper. I may have gone a little over the top now I look again but you get the idea.
The picture has gone a little blocky but thats just because I was working on the small uploaded file - it will probably work better on your original.
Anyway, hope you like it.
Graham