From castle- contact them. You will probably have to buy a new case and fan, or you might get lucky and they send you a fan as a one-off thing. A more durable fan (25x25mm) would be better- there are several threads on the subject if you search older threads in this section...
I think the warmest my ESC got with hard 30 minute run time was 78 degrees. Granted it is about 40 here outside too though. I have sent Castle a email and will see what they say. Being that it is new I would hope they would just send me out a fan. If that one pukes too down the road I will just deal with it.