Hi all! I desperately need your help!

I need to do the following question. Would someone be so kind as to help me with the calculation as I do not have one in my textbook?

Provide for the Interest on the Mortgage Loan. Interest Is calculated at 12.00% per annum. The liability was re-paid By R 45 000 by April 1, 2007. There were no other additional loans or repayments during the financial year, but twelve end-of month instalments of R 1464.38 each are due to be repaid on the Loan, starting at the end of July 2007.

The Financial Year Runs From 1 July to 30 June. The mortgage loan amount on the List of Balances at 30 June 2007 is RR 159 750.00

P.S.
The answer they provide is R 23 220. But they do not show how to get to it.

Please Help me guys? I don't have a tutor or Lecturer to ask as I am studying correspondence.

Thanks a million