S.H.
My husband and I learned in Guatemala. There are TONS of schools that cater to Americans in which you spend 5 hrs a day in one-on-one study (there are so many schools you can pick one that would cater to your children specifically). I studied for 5 weeks, but some people did less. It was enough Spanish to land a job teaching literacy in a women's shelter and wing the rest for a while. You live with a family and your meals are provided.
For all of that, I paid $100 a week in the late nineties. There is a wide range of what you can pay.
It's an experience that your children will NEVER forget, and in my opinion, the only real way to learn a language is through immersion. I stayed in Central America (a cheap flight down and closer to you than LA is) for some years. I have translated for heads of state. All I ever studied was for those 5 weeks.
If you want more detials, PM me.