Dr. John Doe is planning for his golden years. He will retire in 20 years, at which time he plans to begin withdrawing $50,000 annually to pay for his living expenses during retirement. He is expected to live for 30 years following her retirement. His financial advisor thinks he can earn 7% annually before his retirement and 10% after his retirement. How much does he need to invest at the end of each quarter to prepare for his financial needs after his retirement?