I have a ringing in my ears ={

Hello Everybody

I have a problem and I am hoping to get some help.

My church (I know how much people love that starter) hired a couple guys to install a AV system into the church. Now I have a mess that I am cleaning up. The problem is that I have over 30 albums and 25 videos including commercials that I have been a part of the post production on over the years for Fairs and local events or small groups and performers. With this background I have been entrusted with fixing and moving and any thing elseing the live sound side needs for (yep) as little money as possible.

I know video better so I tackled that first and have it working as good as the junk they installed will work.

Now I am into trying to figure out what is going on with the system and I am stumped.

Let me list what we have:
Sound Craft GB2 16 (I have used a Sound Craft 6000)
Crown CDi 2000 Main amp & CDi 1000 for monitors to the choir
JBL speakers of some sort as Choir monitors mounted directly above the pulpit and lectern mics
Home built main speakers from 1975
Tascam CD recorder and a separate CD/AUX/IPOD player as well as for some reason a Tascam 2 deck auto reversing Tape player.

That is on the audio side it.

We were going fine after we moved sound board out of the middle of the church where they installed it to the back. Then we had a power outage and instantly got a feedback and bad ringing anytime people talked. I used the minimal eq and frequency sweeps on the mixer and got it ok. I know I need an EQ but I was told that there is one in the amps and that should be all I need. (got the software and am starting to play with it but such a pain in the...)

Any help or feedback or other questions to help clarify would be wonderful. I really want to get this running good and as I pointed out to start with I have 0 knowledge on live sound.

THanks
Aaron