First I will say that in some departments, GRE scores are a very important component of your application. For instance, I work in a department where each year we get applicants from hundreds of different universities in 70 or more different countries. Comparing GPAs between all the different educational systems is very difficult (we do it, but place relatively less weight on it due to uncertainties). Meanwhile, the GRE is a single standard. Also, whereas some departments in the USA can rely primarily on GRE subject tests, it's quite rare for international students to take those. The bottom line: good GRE scores will never get you admitted by themselves. But in some places at least, poor GRE scores will eliminate you.
Now, as to whether the verbal/writing or quantitative scores matter more, I think this depends heavily on the field. If you were applying to a math/science/engineering program, the quantitative score would be by far most important. It's generally thought that good writing can be taught to you later (and technical writing is different from the persuasive writing the GRE tests you on, anyway).
I assume that if you were applying to an English or fine arts program, the verbal/writing scores would be more important. The fields you're applying to are somewhere in between, and I don't know them well enough to say for certain.
[Edit: see @shion's answer for the opinion of someone who knows more about your particular field.]