The question is:

You want to be able to retire 25 years from now with monthly retirement income of $12000 for 30 years (first withdrawal will be made in 25 years and 1 month from now). You also want to purchase a boat in 15 years at an estimated cost of $60,000. After the 30 year withdrawals, you want to donate $500,000 to charity. You plan to save $2,000 per month for the next 15 years, earn an 8% EAR before retirement and a 6% EAR after retirement. How much will you have to save each month in years 16 through 25?

Not really sure where to start with this one.. Any hints would be much appreciated.