Well, to calculate battery current, you multiply the stated mAh by the C rating. So your 1300mAh x 30C gives 3900mAh, or 39A. If your motor needs 40A (yes, I was wrong, I wanted to recommend the LAST one...), you usually go for at least 10% extra, if not 20, so 40+20%=48A minimum for ESC and battery. The wise choice is 10% extra on ESC and another 10 on top for the battery... so 44A ESC with 48A battery. At 30C, the battery has to be minimum 1600mAh.
The ESC you point out is very good, but still needs a watercooler. So either buy one from the net, there are various models available, or build one.
For instructions, see
http://www.offshoreelectrics.com/inf...olingplate.php
It is very easy to do. I make my own coolers, with copper sheet and brass tubing:
http://forums.offshoreelectrics.com/...p;postcount=40