Do you have your own balled, drilled by a bowling professional? That is the first step in throwing a consistent hook ball. You need to get this done at a bowling alley or a store that specializes in bowling equipment. Next would be the ball itself. They are actually weighted now to emphasize hook or lack there of.
The next step would be mechanics, but without knowing what you have for a ball and who drilled it, the next step would just be a guessing game at this point.
The key is practice though, bowling once a week, 3 games really isn't enough to develop solid consistency. At least at first. you need to go a couple times a week and practice. Once you get to a level you are happy with, then league night should be enough.
I became a decent league hack a few years back. Averaging in the upper 180s. and hitting 200 at least once a series. The key is just repetition. using the same motion every time, but not just for first ball, but getting to know how to throw spares as well. There are nights you just aren't going to hit the strike zone, so the key is to pick up every spare.