I would approach a mortgage broker with a view to ascertaining the lie of the land with all lenders.
If this property is worth around €300k, I'm guessing that it will yield you around €1,250 a month?
How old are you and what's your income like?
Worst case scenario, I'd look at coming to an arrangement with Revenue whereby you pay them a lump sum (maybe €25k if you can raise it) and then pay then over a number of years. Interest at 8% would arise so that's an expensive route, but if you're wedded to the idea of keeping the property and no bank bites, you may have no choice.
As an aside, selling the property and paying off some or all of your own mortgage may offer an attractive rate of return (if you're not on a tracker) and may make your life easier.