What do I need to mix and record my church service live

I currently use an old Allen&Heath ZED 32 chael mixer. We are taking the mix from an AUX out and sending that to our camera XLR to record our services. The audio isn't very good due to "dirty" power. It sounds great in the room but the recording is bad and takes a lot to clean up in Adobe Audition. We are using an iMac for all the editing. I'm looking to switch to a digital mixer and would also like to send an output to my iMac to record multitrack in Audition. Can you recommend the best solution for this?