Here are the links to calucating how much you will need to attend Ivy League universities and how much financial aid you can expect. Run these financial aid calculators and see how it all shakes out for your family.

Harvard: https://college.harvard.edu/financial-aid/net-price-calculator
Yale: http://admissions.yale.edu/yale-net-price-calculator
Princeton: http://admission.princeton.edu/financialaid/estimator