For under 1,000 its difficult to recommend a nightclub system, or call a system a nightclub system.
If this is a bar and you need to keep the noise level down, but still want some dynamic sound, I'd probably just use the 8" JBL Professional Control series speakers.
Two of these JBL Control 28s:
http://www.fullcompass.com/product/286360.html
A dbX DriveRack PA:
http://www.bhphotovideo.com/c/product/261160-REG/dbx_PA_DriveRack_PA_Multi_Dynamics.html
(This has a built in crossover, limiter, EQ, compressor, sub-harmonic synth, and for 100 bucks extra an RTA mic, really nice unit. Since your going to keep your levels down because of the neighbors, you can use the sub-harmonic synth to give your sound a bit more dynamics and depth).
For power I'd pickup a Crest Audio CC1800. It's more power than you need, but if you want to add another pair of speakers when budgeting allows you'll need something 4-ohm stable (two Control 28s at 8-ohms in series would be 4-ohms).
By the time you add in cables and everything your over budget, but you could buy the speakers first, then the amp, then the processor. Really with a DJ playing you need the processor though, especially on a small system like that because otherwise they will run you out of headroom before the night even gets going.
You really need subs too when budget allows, but, if you have neighbors, that can be difficult. Horns work better for directionality, playing with placement to keep the bass on the dancefloor rather than all around the room and into your neighbors, figure out where the building tends to shake and add notch filters... we can figure all that out when you get to it though.
the 12x12 must be a typo for a nightclub, because, my office is bigger than 12x12.
Lemme know if you have any questions,
