The scores don't need to be updated regulary, only when needed. Like for example, who gets most points within 1 hour. I don't think hash tables would be the right choice for that. Also I'm that new to mirc scripting I haven't experienced them at all.
What comes to counting, so far no good. I fixed few bugs that made the script not to work. I managed to do that myself. I looked into those four options Masound said and I think $read would be the right choice here. However, I'm struggling how to match the data. I'm quite good when it comes to editing something already there but writing something new... I need to learn mirc scripting a lot more (at least personally I feel like: "ohh man, how am I supposed to make this work... *headache* "). :S