It's really hard to say what would be best. In my opinion most of the square space or wix sites I have seen that are put together by non designer types look like a jumbled mess. That's just a personal opinion.
If it were me and I knew nothing about design or dev I would probably pick up a hosting account with any number of hosting providers (i.e. Media temple, Bluehost, Dreamhost, or go daddy ). A shared hosting plan should be adequate and inexpensive. At this point you can call the host and they will likely be able to walk you through installing Wordpress on your server. Then after that is finished you can pick up any number of Wordpress theme templates and then via the Wordpress dashboard which is fairly straight forward, you can install your theme (again any good hosting company should be able to help you with).
Just by a quick search i was able to find these theme which would be a great place to start.
http://themeforest.net/category/wordpress/nonprofit/churches
The highest priced theme I can see there is about $60. You can change images out to customize to your liking.
There are TONS of options out there on the web. Some free. You just have to look. You will find something that suits your needs.
Anyhow, good luck to you. I hope you find that answers you need. Post any questions that you might have and I will try and help where I can. There are some other great people in here that are supremely helpful as well. They are likely to have valuable input.
