It will help. A full pension requires 40 years of PRSI contributions paid or credited. So, for example, 34 years equals 34/40 of the full rate. If you retire early you may be able to get credited PRSI contributions but it would seem premature to go into that now.
The main difference between your scheme and the previous scheme is that "normal retirement age" increased from 60 to 65. Retirement before normal retirement age usually means an actuarial reduction (CNER). For you, retiring at 58 rather than 65 means your pension for 30 years service would be reduced by almost 1/3. You could retire with a deferred pension at 58 etc. and get the full pension amount from 65 but this is probably not a runner as you would have no income of your own in the meantime - unless you were looking at alternative employment. With a deferred pension you could not access your AVCs until 65 also.
And yes, just like in the older schemes, your pension is based on final salary (and any pensionable allowances).