Answer: Here are few thoughts/ideas/questions:
1. How involved is your church going to be in the process, in the ministry? Their involvement and control will affect everything you do in the ministry including how you advertise. If they are going to maintain control over the ministry (even if its to be a city-wide ministry that may move to other churches from time to time), then they will more than likely prefer to have the information on their website to show ownership. You mentioned that they are slow at making updates..I would talk to them about this process and how critical it is to have the updates done quickly. Perhaps you could be given access to make the changes yourself.
2. If your church is simply the place you are starting and will not be taking ownership then I would build your own website and/or facebook page.
a. Website: There are some great free website companies out there. I use Weebly to design the www.TheSinglesNetwork.org site. Because I wanted more options, I did go pro and pay a reasonable fee each year. If you do design your own website, be sure that your church creates a link to your site. Your church could put a small paragraph about your ministry including the leaders names, phone numbers, emails, etc. plus the link to your website. You could encourage any churches that you are working with to do the same.
b. Facebook: In today's advertising climate, it seems that everyone needs to have a facebook presence. If you do create a website you may also need a facebook page. However, as an alternative to developing a website, you could simply create a facebook page only (that has a linkable url address). The advantage of a facebook page is you can add members, post comments/thots/prayer needs, post events, attach files such as your guidelines/purpose/vision statement, articles, post photo's of events, advertise events. The of value of facebook over just a website is the interaction to the public. The disadvantage is the limitation of graphical design and some custom features that only a website can do.
3. Marketing Ideas: Go tothis page on my site, scroll down to marketing and download some creative ways to market your ministry. There is also a great MP3 audio resource for those starting a city-wide ministry.
For info or questions, contact me at Kris@thesinglesnetwork.org or 919.434.3611