1) The easiest and simplest way to get the balance after 4 years is to do an "amortization schedule", such as this one: http://www.calculator.net/amortization-calculator.html?cloanamount=2250000&cloanterm=20&cinterestrate=4.50&printit=0&x=56&y=13
2) Alternatively, you can calculate it directly as follows:
a) - Find the FV of the $2,250,000 principal @ 4.5% compounded monthly, which should give you:
$2,692,832.35
b) - Find the FV of the 48 monthly payments of $14,234.61 each @ 4.5% compounded monthly, which should give you:
$747,086.91.
c) - Subtract b from a above and you should get the balance after 4 years:
$2,692,832.35 - $747,086.91 = $1,945,745.44 - Balance after 4 years.
You can round it to $1,945,745.
