[LAU] OT: Sound system for small club/bar?

I've been asked to help put together a PA system for a small bar/club. I know nothing about how to do this, other than running sound for my own bands when needed. But I'm trying to do the best I can. It's too small a club to justify hiring a really experienced sound engineer. They mostly book acoustic artists, but need enough power in the PA such that when they have a live rock band, the vocals can be heard over the din of distorted guitars, basses, loud drums, etc. They also sometimes run DJ stuff through it, though not very loudly. The club layout is a long, deep bar space, with the band set up near the middle, and the audience on the sides, a low wall creating a narrow corridor at the entrance, and very high ceilings. The walls are plaster/wood, with (very cool) art hanging on them. The street side has an entrance and windows covering nearly its entire surface. There are side entrances too that go to the kitchen and restaurant. Top view here: http://www.restivo.org/misc/topview.png Elevation view here: http://www.restivo.org/misc/elevation.png They already have a nice Mackie mixer and a couple mics. They were using a set of Bag End fill-in speakers and a Crown power amp, but that just didn't have enough power and clarity when used with a band situation. So they just need to replace the speakers and power amps. It's a small room so it's not like they need any kind of massive system. But they do want clarity and headroom, and the ability to handle the occasional rock band. I'm thinking of recommending they buy a pair of these, and mounting them where the existing speakers are: http://www.guitarcenter.com/JBL-EON315-15--280-Watt-Powered-PA-Speaker-1051… Do you think that's the right call for this room? Is that the right location for them too? Any ideas what kind of research I should do in order to determine what would be the right thing for them? Way off-topic, but I've played this room and it's a wonderful space from a vibe/attitude/audience standpoint, the people who own it are fantastic, and I want to make sure they get the best sound possible out of it. -ken