Painful Epiphanies

As I was writing last Sunday's sermon, I was pierced by a bitter irony: we've been going about growing the evening service wrong, and I don't know how to do better.
We have a pretty stable worshiping body of about 30, which is small compared to our Sunday morning services. I would feel really great about this if the group were not all members of the church who also attend a Sunday morning service. Clearly we're meeting some need for them, and I want to continue, but I also want to recover our original aim of providing informal worship for neighbors who don't attend church and for vacationers and other transients looking for an evening service. Early in the summer, we did fairly well with "boat people," who come to town by water and dock at the town docks. But now we're down to our regulars (whom I love, and certainly don't want them to go anywhere else...come again, and bring friends!) and I'd like to try to do a good job at finding and forming relationships with those folk who are not regularly worshiping with us.
I just don't know how, not really. So far the best idea I've come up with has been twofold: hang out in the local coffee shops, get to know people and then invite them, and create a coffeehouse atmosphere where we are: coffee, flavored syrups, steamed milk...
I can also (and will) ask the "young adults" in the church what would make the service more attractive to them: do we need to change the time, change the format, advertise in some particular way or place?
I'm frustrated and hopeful; I told my senior pastor today that when we evaluate the service in 5 months, I want to at least be able to say that we've done the very best we could do. And I think we have as far as the service itself goes. But preaching Sunday reminded me that we're here waiting for people to come to us...and I don't think that's going to work. Because it's not about growing a service or having great attendance, but about helping people be in relationship with Christ and the church...