I think you are coming at this from the wrong end. First, what do you want that you don't have now? Perhaps even sound from the worship team throughout the room? Perhaps being able to hear the pastor anywhere in the room? These are guesses because you haven't told us.
I don't like powered mixers for a number of reasons. First, the power is usually in the wrong place. You want your amps close to the speakers, not close to the mixer. Second, the form factor. It is easier to mix when the faders are near horizontal, not vertical. Third if your church grows, you will want to change the mixer or the amp and it is inconvenient to have them in one box. Last, with the right information, this is a real good time to buy the right used analog mixer. A lot of people are switching to digital and there are a lot of good analog mixers out there. There is also a lot of worn out never was much good junk out there so you need a guide. Last, A good mixer and a good amp can cost less then a powered mixer.
I get that you want to spend as little of your churches money as possible, but the reason that everyone jumped is that people in general and churches in particular tend to wast to much money on the wrong stuff. It is said that most churches buy 3 sound systems before the get it right.
Your options are about like this. Make your best guess, spend $350 or so on a powered mixer. Figure out that it doesn't solve your problem, spend $600 or so on the next step, Figure out that isn't it, start over and spend $4000 on a new system from the local music store, Now you have a real problem. First the system isn't great but it doesn't suck and you can't spend anymore, so you are stuck with it. After 10 painful years you bring in a pro. He tests the room, makes some computer models, and recommends that you replace half your stuff. That will cost you $2000 for the right stuff and $1000 for his services.
You take him aside and ask what it would have cost to start with an empty room and he tells you about $3000 plus his $1000.
OK so I am the bad guy trying to make your problem complicated, why don't I like churches. I am a Christian, and a church sound guy, I run sound for my church, and oversee the tech team. I have run sound for hire for other christian events and other churches. I like church sound and I think it is important. I have heard a man tell our church that he came out of curiosity, he stayed because he enjoyed the great music. As he hung around he heard the plan of salvation and understood and accepted Christ as his personal savior. I heard that testimony through a good system. His voice was good and clear and everyone could hear him. I had my hand on the fader to make sure of that.
Look around, talk to other churches, find a good sound professional, check his references to be sure he is good, then hire him and do what he says.