I don't know anything about buying back years.
If she retires at age 60 she has the potential to gain full rate paid Prsi contributions up to age 70.
She currently has 89 A.
If she gained 52 contributions from age 60 to age 69 this would gain her 468 extra full rate paid contributions.
This would bring her to a total of 557 and would allow her to qualify for a partial state contributory pension.
She can achieve these extra contributions by either taking up class A paid employment at age 60 or drawing down a minimum of 5000 euro per year from an ARF.
If she takes up class A paid employment at age 60 for a minimum of 1 week she would gain 2 years of change of status credits. This gives her an extra 104 class A credits.
Her total of reckonable contributions would now be 661.
A full deferred pension at age 69 is 320.30 euro. She would qualify with her level of contributions for a partial payment of 101 euro per week.
If she doesn't intend working beyond age 60 and decided to use an ARF, she would need at least 45000 euro in AVCs after claiming any extra tax free lump sum available to her. She would just need 1 week of employment to secure her change of status credits.
Maybe she could manage this in addition to buying back extra years in the next 6 years.
She could also, after working at least 1 week at class A, make full rate voluntary contributions up to age 66 and possibly up to age 70. These would cost her 500 euro per year.
She could possibly make out a plan if she had less that 45000 euro in her ARF to mix Voluntary Prsi for some years with ARF drawdowns of 5000 euro for other years.