Salt and Pepper hair..considering colouring it.. advice please (photo)

[StillMedusa]

I've been 'going grey' deliberately for about 6 years now (previously coloured) I'm 55.
But.. I have white where the front parts, scattered grey throughout and the back is still mid/dark brown. I was hoping for glorious silver hair but looking at my Mum, who is 76 and not much greyer than me, I don't think it's going to happen any time soon.

I like the lack of expense having natural hair but I feel and look washed out. But I don't want blocky brown hair any more, and the one time I went blonde I looked truly dreadful..I have sallow skin and looked like a corpse (my hair isn't as yellow as the pic looks though!)

Can any one suggest anything?

2Bornot how long does the semi-permanent brown last for and do you do it yourself? I like the idea of a colour that will fade by the time roots are noticeable. If there are any good brands out there would love to know more. I think StillMedusa's hair looks great in it's natural state btw.