Use the payment formula.
Pmt = L [ r ( 1 + r ) ^ n ] / [ (( 1 + r ) n) -1 ]
L = $23,000
r = 0.0999 /12
n = 60
Make the necessary substitutions and you will get the following:
Pmt = $488.57 for 59 months
= $488.50 for 1 month (last payment)
Total payments: $29,314.13
Total finance charges: $6,314.13