Try the data provided by Worldbank in their searchable databank. Under database tab choose Quarterly External Debt Statistics. Look for service on foreign debt in "QEDS/GDDS" under the series "Total debt service." Look for debt levels in QEDS/SDDS under various series.
You must choose country, series, and years. If you miss one use the "Select Variables" tab to go back. After all are entered, follow the link "View Data". If you have chosen more than one country, each will display separately. Toggle down to change the country that displays.