We've been playing without a drummer at our church since last Christmas, when our drummer and group leader had a disagreement which led to a falling out and our drummer quitting the band. We are now two acoustic guitars, a piano, a flute, several singers, and me on bass. I think it's working out just fine. Since our ex-drummer's playing was so restrained, we don't really miss him, and our timing hasn't suffered at all. I've always been of the opinion that time is everyone's responsibility, so everyone has picked up the slack, and our sound hasn't suffered at all. And our stage is a bit roomier now. We did have to drop "Little Drummer Boy" from last Christmas' setlist, though!
My advice would be to just keep going the way you are. As musicians you occupy a section of the sonic spectrum, and guitar, keys, and bass (and singers, I'm assuming) should cover it nicely. With the tempo anchor (I like that term!) of the drums gone, all instruments will have to cover for the missing drums, but if you're all the slightest bit competent musically then that shouldn't be a problem.