dyeing grey hair blonde

 

I've had very light bleached blonde streaks for years now, but at this point my hair is looking too blonde.  My stylist says its because I have so much grey on top now that we've lost the base contrast, and she can't do the slightly deeper colour streaks on grey hair, so its all bleach on top at this point.  She says we now have to colour (dye) first, and then add highlights.  Is this right? 

 

What we've done lately is do all the streaks, and at the end just streak is some darker toner, and then it looks great, as the toner just looks like low lights.  Its just that it only lasts a few weeks.

 

I have a very light ash brown base, or at least I used to.  My hair is about one third grey, but that's mostly on top.  Its still darker underneath.   This salon uses Goldwell, and she said that you can't dye grey hair really light blonde, cause it just won't colour grey, so we have to go a bit darker and the lightest we can use for the base is a level 8.  I think she said 8N.  I do so love cool beige blonde hair, but she said that beige hair looks flat and there is no life to it.   I'm rather confused, as I've never actually had my hair dyed before.  I have a cool toned skin (Summer in the colour wheel) with a lot of red in my face.   What colour base should we go with in Goldwell?

 

This is a pic of the colour I would like to get.