You can qualify for a pro rata contributory pension with a minimum of 260 paid A contributions alongside your D contributions. When you retire at age 60 sign on for Jobseekers Benefit or A class credits until you reach age 66. This will increase your ratio of A's versus D's and increase your contributory pension amount.
If you can manage to set up an ARF at age 60 you would be able to gain S class paid contributions which would improve your ratio and allow you to exceed the 520 paid contributions needed to get the normal contributory pension.
If you cannot manage to set up an ARF, then at age 60 if you worked part time and earned at least 38 euro per week you could gain extra paid A contributions. You would need to work for 109 weeks to reach 520 A paid contributions and then you would probably achieve a higher level of contributory pension. You would only need to work 4 hours per week at minimum wage to gain an A class paid contribution.