How long between 1st session 2nd session of lightening hair for Ombre?

[youvegottobekidding]

My hair was lightened for Ombre 2 weeks ago, the hairdressers couldn't lift to the desired shade of blonde in the first session as I had a lot of colour build up on the lengths, so I'm currently left with a sort of light warm caramel brown slightly yellow tone!

I reckon I could go for a second session in a couple of months but it's driving me nuts with it like this! I really want it at least a bit lighter, more of a blonder shade. If I got booked in next week would it be too early? Is 3 weeks long enough for my hair to rest? My hair isn't in bad condition, but it's not in great condition either, it's just a tad on the dry side. I don't want it breaking off. What perplexes me is that years ago, I went to a local salon in the villiage & they did cap heights (my hair was already coloured) & they took me straight to a blonde blonde, no yellow, no done in stages, no problem. I'm not sure why the other hairdressers couldn't. I may actually go to them & ask them to do it. I hope I've made sense!!