grey hair

hello everyone-nice to meet you all, this is my first time here today.  here is my delima...i am 42 years old, and have been greying since 14...hairdressers tell me i'm completely grey, but i have been dying my hair blonde for years, since it doen't show my roots as bad.  my hair is very light from all the proccessing over the years...i now have shoulder length hair and would like to go back to my natural grey ,slowly, by letting my roots come in and by highlighting my hair grey.  no one in town will do this for me, even though this is what i truely want to do, so i am looking for a good silver color to highligh my own hair...any suggestions on what to use, and where to order the color...i plan on buying a frosting cap, and doing it that way...thank-you

As far as the colors for highlighting try www.sallys.com they should have all the products you need, everything else I wouldnt have a clue about.