Mac connection problem - Crash just before getting in game

Hello guys! So, I just got a new Mac (bought from a university, so the mac is fully updated, everything works fine except for League..). I use to play on a windows 7 lenovo, had few bug here and there, but nothing that kept me away from playing.

Here are my mac spec : Software : Mac OS X Lion 10.7.5 Processor : 1,83GHz Intel Core 2 Duo Memory : 3GB Graphic : Intel GMA 950 64 MB

So what happens : I have access to the lol client (store, profile, friends profiles, I can chat, etc.). i can launch or join games, I get to pick my champion like everyone else, but as soon as I reach 100% in the loading (when my champion is about to spawn in game bassicaly) my game just crash. I get Bugsplat, then a message on my mac that says something went wrong. I only tried this in custom (I wanted to set my settings and all before I got into a real game). I tried various champions (caitlyn, shyvana, miss, tristana, sona, orianna... I tried over 20 customs) they all crash at the same moment... It's really frustrating since my laptop is just to laggy in game (my laptop is not really perfomant). If anything, I can post some of my logs here if there's anything. I hope someone can fix this problem cause it's really frustrating. Has been happening for 3 days now and I've tried every possibilities on League's official troubleshooting page.. I really don't wanna go back on my windows 7. Thanks! Genneuhx, a summoner who just wants to play!!!