Dual subs and or speaker uograde

I have Monitor Audio Gold 300s as my front mains. All Gold speakers 100s for surrounds, 300Gx center, Gold GX rear surrounds.
Paradigm Sub 12 Reference as my sub.

Room is 10'w at front, and 18' wide at rear. 7.5'H, 22' long and 13' from front wall I have my 3 theatre seats,

I feel I need a little more umph for watching concerts on DVD.

I have about 15k to spend.

I am considering dual Persona subs or dual B&W DB1D subs to augment bass.

Other option is Persona 3F with 1 Persona sub ( a little over my budget) or Persona 3F with 1 B&W DB1D sub (on budget) or Persona 3F and 2 SVS Ultra16 subs.

Another options is GoldenEar Triton Reference, but due to 10' front wall with 100' screen, I'd need to put speakers fairly close to front outside walls 10-12"

Appreciate your opinions.

My audio store sells all except GoldenEar. They have given me great service.

My amp and preamp are NAD M27 and M17. I'm happy with the quality of the sound of my Monitor Audio 300s. Great sound. Not enough umph.

Thanks Roger
All the talk about how fast some subs are is pure blather. I can outrun almost all of them.
I have 4 in my home theatre huge change from one ,I have two in my dedicated audio room but am remodeling a stand alone 16'x24' building on my property just for dedicated audio .I will run four there when complete. As Erik stated the single biggest upgrade I did within reason was treatment period.
Sorry to ask this question, but what is REW, where would I find the tool to use it?

Okay got it 
Room Equalization Wizard.
REW. Now where to get it and I'll do some homework.