My ash blond highlights are turning gold!

you could try using blonde-shampoo, like that john freida stuff. try using the one for platinum/champagne tones rather than the one for honey/gold or whatver it is. it mignt help. and i like this shampoo i always use it.

try using shimmering lights shampoo, or any shampoo with a blue violet base to counteract the gold.  It should work

How long does the colour stay nice for before it fades? 

L'Oreal Recital Preference is supposed to be a fade-resistant colour (I use a purple tone of it and it's beautiful), and they do blonde shades too.  If that doesn't work, you could always put darker streaks throughout your hair, like a light-brown or something - that would look nice, and it would blend with the blonde giving a more natural look (instead of a faded look).

Louie

I had some highlights and lowlights put in my hair about 10 days ago.
For the first couple of days, my hair was pretty close to its natural
colour (which is dark ash blonde) with a few very pale higlights thrown in.

I don't know what's happening, but my hair is turning gold! It's a very
pretty shade of gold, but it clashes with my skin colouring (very pale
or "cool"). I use Biolage's Colour Care shampoo and conditioner to
preserve the colour and I stay out of the sun as much as possible, but
still my hair colour is changing all on its own.

What should I do to fix this problem? I wanted a darker shade of blonde for the Fall, so perhaps a toner isn't the way to go. Would a semi-permanent gloss be better?