Did I get this right?

Did I get this right? If I put $500 into a savings account at the end of each quarter for 18 years in order to save up some money to assist my son with college tuition. I invest the money into an account with a fixed annual rate of 8% and interest is compounded quarterly.

How much money will I have saved up at the end of the 18 years? and How much interest do I earn?

For the first one I believe is 500(1-(1+0.02)^-72/0.02) = 18,992.03 is what i would save up right?

Then how would I calculate the interest that I would earn? I'm stuck a bit.