Purple/grey dilemma!

Heya,

I currently have purple hair (Directions Violet over a faded Live XXL Cyber Purple over a faded out Directions Magenta/Rubine mix), for the most part it's a lovely toned purple and holds the colour fairly well with diluted top ups about every 2-3wks but all around my hair line, temples and parting I've got loads of grey hair :'( and whatever I try colour just doesn't stick to it for more than a week or so regardless of if it's bleached, permanent dye or semi.  So do I keep persevering and just keep redoing it (unless anyone has a magic trick to make it stick!) or do I embrace my old age and try to get the rest of my hair to match and rock the silver grey look!  My only fear is that as I'm naturally dark and my hair is pretty stained after years of colouring it might be a bit of a job to get from here to a nice even light base to work with plus I'm scared that if I do go to silver grey then I won't be able to go back again and I will officially be a proper grown up old lady!!

A xXx