One suggestion would be to go to the denomination that your church is affiliated with and see if they provide any free web space and tech support. I am in the process of creating a site for our church using web space that is provided by our denomination.

For suggestions on content, it might be a good idea to google "church websites". Here is one link that I found particularly helpful. It might help you avoid getting bogged down with eye candy and instead help you to focus more on content, at least initially.

If your denomination does not offer free web space or services then you'll have to obtain a domain name and web hosting services and then get started. Someone in your church who knows how to develop web pages will have to work on it, or someone will have to learn. There may come a point where it would be wise to hire someone to do it for you, depending on how complex you want the site to be and how much talent there is in the church body for this type of activity.