I need help finishing this retirement plan. I need to adjust calculations somehow to factor in the $300,000 that has already been saved into her retirement account at this point. Need to find the monthly payment that is needed in order for her to reach her retirement goals.

B C D E F 1 Charlotte Retirement Plan 2 Age 42 23 20 85 12 $ $ $ 100,000.00 250,000.00 125,000.00 0.05 2.65 9.5 5.5 3 Years to retirement 4 Years in Retirement 5 Life expectancy 6 Number of Payment per Year 7 Amount left to heirs 8 Cost of vacation home today 9 Salary 10 Salary Growth 11 Inflation (%) 12 Investment growth before retirement (%) 13 Investment growth after retirement (%) 14 15 16 Calculations In Retirement: 17 Number of Periods in retirement 18 Interest Rate per Period 19 First Payment in Retirement 20 Growth Rate Per Period 21 PVA Calculations: 22 23 24 PV of Retirement Annuity 25 26 27 FV of Vacation Home at Retirement 28 29 FV of Amount Left to Heirs BO 31 Lump Sum Needed 32 Calculations In Working Years: Number of Periods to retirement Interest Rate per Period Lump Sum Needed Pmt. Calculations: 240 0.458% $ 31,995.04 0.221% 0.451445931 0.551068275 $13,471,595.42 $7,423,768.85 276 0.007916667 $8,187,929.52 1.007916667 8.814485252 $928,917.49 0.969837609 $7,353.93 $7,582.64 PMT Needed per Month $ 456,242.72 $ 307,917.95 $8,187,929.52 min 36 37 B C D E F 1 Charlotte Retirement Plan 2 Age 42 23 20 85 12 $ $ $ 100,000.00 250,000.00 125,000.00 0.05 2.65 9.5 5.5 3 Years to retirement 4 Years in Retirement 5 Life expectancy 6 Number of Payment per Year 7 Amount left to heirs 8 Cost of vacation home today 9 Salary 10 Salary Growth 11 Inflation (%) 12 Investment growth before retirement (%) 13 Investment growth after retirement (%) 14 15 16 Calculations In Retirement: 17 Number of Periods in retirement 18 Interest Rate per Period 19 First Payment in Retirement 20 Growth Rate Per Period 21 PVA Calculations: 22 23 24 PV of Retirement Annuity 25 26 27 FV of Vacation Home at Retirement 28 29 FV of Amount Left to Heirs BO 31 Lump Sum Needed 32 Calculations In Working Years: Number of Periods to retirement Interest Rate per Period Lump Sum Needed Pmt. Calculations: 240 0.458% $ 31,995.04 0.221% 0.451445931 0.551068275 $13,471,595.42 $7,423,768.85 276 0.007916667 $8,187,929.52 1.007916667 8.814485252 $928,917.49 0.969837609 $7,353.93 $7,582.64 PMT Needed per Month $ 456,242.72 $ 307,917.95 $8,187,929.52 min 36 37