I know it's a city car with small capacity but I need to know if it manages long distances as well(need to say that I am not a speedy driver). Please help!
As Charles says, it will cope with it fine with a few basic precautions. I would have said drive it fairly gently, but it sounds like you do anyway. You may get bored, so throw in a few breaks for both yourself and the car.
In fact, it may do the car good if it's been dragged around in traffic most of the time - clears the cobwebs.
I took a Fiat 500 on a 1000 mile round trip in about 1974 that only had a 499cc engine i had to ease my self out of the car every time we stop my brother-in-law was over 6 foot his head was touching the canvas roof but we had a good time and that engine was air cooled you do it and enjoy your self