Tax money goes to good locations, and things you or people you know use every day. Roads, schools, and the local law enforcement come to mind.
Looks like there is a correlation between test scores and funding, but it's not statistically significant.
According to a review of over 400 studies, "there is not a strong or consistent relationship between student performance and school resources, at least after variations in family input are taken into account," according to a paper published in the journal Educational Evaluation and Policy Analysis.
This chart, http://www.heritage.org/static/reportimages/796DF8C7C231CFFE..., would seem to suggest while per-student education spending has doubled between 1970 and 2005, scores haven't really improved.
Do you have any evidence that increasing funding will improve results?
Pay particular attention to the McKinsey report results, which found that a teacher that is a standard deviation better than the norm adds $20k to a student's lifetime earnings. Two standard deviations gets you $32k, or $640,000 for a class of 20. Teachers' starting salaries are $39k/year in the U.S., but in educationally top performing places like South Korea and Singapore teachers earn more on average than lawyers and engineers.