Help with battery purchase

Hello guys, I don’t really have a lot of plan of cars, just use them to get from A to B. After my battery has already been discharged 4 times (3 times the start was not possible), I think it’s time for a new one. Unfortunately, this presents me with the problem, which one should I buy? Image org battery: http://postimg.org/image/6tej9yxn9/ Now I have read and have encountered the DIN ETN problem. 1. Don’t I know if DIN or ETN is printed on it?? 2. It’s hard to find a battery with these specs, too arg higher I don’t want to go with the A, because I don’t know how much the light mesh can spit out or how many amps the electric can make without damage. If I go too high with the Ah, it can’t be that the battery is completely charging right anymore? It would be nice if you could explain something to me with A and Ah and what has an effect on which and possibly a link to a good battery in Amazon The one with my Twingo runs or differently. Thank you! Maybe still important: price expectations about 100 euros. Own a Twingo of the II series, everything else I would have to look up first, if that is important. Manuel