5000 is loads.
what you need to do is get rid of your thoughts around engine size. You are doing a fair mileage. you need to buy a nice big car you are safe in and a good engine that won't strain.
Thankfully, most people in Ireland will happily spend 20-30k on a car and yet worry about the extra 200euro in road tax.
So, larger cars are cheap as chips.
So hop over to carzone.ie and search for diesel cars from 99-02 up to 2.0 in engine size and see what tickles you. Most of these cars will have about 75-120k mileage... so go for something towards the lower end of the scale and you will likely get a comfortable and well equipped car that will last up to 150k+ with just the usual jobs you would expect.
Well, that's what I'd do anyway.