Stephanie has purchased a decent apartment in the suburb of Nilai, Selangor, 8 years ago at an undisclosed price. She took a home loan with a 30-years repayment term at 5% interest per annum, which requires him to make $1000 in monthly instalments. In the intervening five years, the Central Bank has announced an interest rate cut to boost the economy; therefore, Stephane plans to refinance her home loan; that is, to roll over her loan outstanding balance into a new loan with a lower interest rate. Her current bank is offering a new 30-year loan at a 4.0% interest rate per annum.

(Note: calculation should account for monthly compounding interest and the payment will always happen at the end of the period)

1. Compute the new monthly instalment in $, if she opts for the new home loan with a lower interest rate.
2. If she prefers to pay off the new loan in 25 years instead of 30, how much will the new monthly instalment be?
3. If she opts to continue paying the same amount as the current loan but with the new interest rate, how long will the loan be fully paid off?
4. Supposed, she is willing to continue paying $1000, but she wants to pay off the loan in 25 years. Compute the additional cash she needs to borrow today as part of the financing.