All the banks have some kind of mortgage calculator which will give you an indication. If I plug this into AIB's it suggests a maximum of 231,315 on a property valued at 257k, which means you'll need a deposit of €25,700. But before you get excited you'll also need about 5-7k in additional funds to spend on stamp duty, legal charges and property tax. If you've managed to save 10k in 6 months however, your best best is to consider saving the same for another 6 months to give yourself a better chance - I walked into my bank 3 years ago with 26000 saved (no family help available - they are extremely poor), and the bank would not even let me apply because I hadn't enough saved for stamp duty and legal costs.
Go talk to a broker though, they can give you a wider view.
As for your age, it sounds more difficult than it is - some banks (eg PTSB) will lend up to 70 if you have a pension so this isn't so bad as you think.
I was in the same position for years - lower income being the primary issue, and only started this year aged 49, but at end of day its still largely the same criteria around earnings that mattered.