In order to get sufficient volume for good recording levels, your mixer needs to be operating at higher output levels than you usually use for live sound, especially in a church setting. In order to get around this you can use an auxiliary output if there is an extra one available. By doing this you can increase it's level to what you need for recording. This gives you the added feature of a separate mix for recording. This separate mix can be an advantage because you can now feed as much of each microphone as you need to tape, independent of the main speakers. It can also be a disadvantage because you need to monitor what you are recording more carefully since it is not what you are hearing in the room. It is also difficult and sometimes impossible to get a stereo recording this way.
Using a Preamplifier:
The second, and simpler, choice is to add a stereo line amplifier to the system. This unit simply connects between the output of the mixer, and the input to the tape recorder. It boosts the signal to the level required for good quality tape recording.