Firstly the acoustics in a church do lend themselves to a huge rock
sound,which is a problem in it's self. However try a small towel
rolled up (or possibly two) and taped to the bass drum head (s) Also a
small piece of tape on each tom batter head will help and on the bottom
heads if that's not enough .You don't say what type of heads your using
, so if finances allow you might want to change to a heavier ie less
resonant type.
What you must remember is that rock music is, by definition, loud .How
about the res t of the band turning down a bit (or even a lot!) this
could also improve th e general balance and enable you to hear each
other better .If anybody objects politely suggest to them that they may
be in the wrong band!
hope this helps
Chris