Having spent several years in the workforce, Mandy is now preparing to save for her retirement over the next three decades. Her strategy involves contributing $1,000 per month to a stock account and $500 per month to a bond account. The stock account is anticipated to yield a 12 percent return, while the bond account offers a 4.8 percent return. Upon retirement, Mandy intends to consolidate her funds into a unified account generating a 6 percent return. What would be the monthly withdrawal amount Mandy can sustain for a 25-year period?