The Sims 3 Season keeps crashing on my MAC HELP!!!

So I know this isn't exactly the computer stuffing it up because its the best Mac you can get, its made for games isn't it? :C anyways now and then it would stuff up but until this month it stuffs up not long into game play, sometimes force close, and sometimes freezing where I just end up turning it off or exiting (I only just figured out how to do that like, yesterday). 

Also a long time ago I downloaded some stuff from the exchange which was soo cool, but after awhile it made create a Sim stuff up with crazy colours and what not and sometimes carried out into game play, so I took all the dlc off which almost completely fixed the game except after awhile it would freeze. So I took everything off and reinstalled it and that made it better for a long while but sometimes in create a sim it stuffs up again and until recently is doing it more often then I can handle.

So please give me your ideas on how to go about this because its come to me basically not being able to play which sucks because I just got seasons and I really wanna check it out. 

Also not so keen to unistall and re-install all my Sims, because it takes so long and last time it obviously didn't completely work. But if anyone's convinced that will work I will do it. -Also if anyone has resetting my Mac in mind, I'm OK do to that, if it will work.