Sounds like you will be forced to use public schools, all public schools are in Spanish, there may be exceptions, i dont have kids. English is 1 hour a day, the rest of the classes are in Spanish.
A lot of people are very dissatisfied with public schools and try to get into a Charter school if they can. Failed that a lot of people that can put their kids in Private schools.
Not sure of your income or life style, but most expats live just fine on 3,500 a month or less, locals live on a lot less. Obviously none of those have more than 1 kid in private schools. You may find that you may be able to afford private schools after all with some adjustments.
There is a big group of people doing home schooling and in PR there are support groups and the government does not get in your way in the area of home schooling.
