I am not a driver but from what you have told us, I would stick with what you have. It's a reliable little goer, you know it's history, gets you from A to B and very low mileage, what's not to like?
We have had our Rover 25 for 17 years, has just passed it's MOT, we only use it 3 times a week hence 41,000 on the clock. It's going to be our last car, wouldn't part with it. Plus the amount you would spend on a different car, you will probably need to pay your next fuel bills etc. IMO