Which component to upgrade to improve bass control?


Adding Symposium shelves and rollerblocks to my monitor (Silverline SR17.5) equipped system definitely helped but bass is still not nearly as controlled as I'd like.

Until we move into a different house where I can have a dedicated room for audio, I cannot use subs or add panels, traps, etc. to the room.  

So, I'm left with the possibility of upgrading a component but I have no idea whether my integrated (Wells Majestic), transport (Sim Moon 260) or DAC (Aqua La Voce S2) might be the best candidate for upgrading.

DAC UPGRADE ?
Are R2R ladder DACs simply weak in this area?  Searching the threads, I found a reference to DAC power supplies having a strong influence re: bass control but I lack the technical expertise to utilize this fact. Please keep in mind that I do not enjoy DACs that prioritize resolution above all.  

TRANSPORT UPGRADE ?
Would replacing the Moon transport with say, the new Pro-ject CD Box RS2 T be a better choice? 

INTEGRATED UIPGRADE ?
Would an amp with more grunt be the best choice?

I can only upgrade one of these at this point.
Budget:
Integrated: 5K
Transport: 3.5K
DAC: 5K
stuartk
I guess I'd better state that I'm aware that what I'm after may simply not be possible by upgrading a component. That's fine. Just thought I'd ask, as I'm no expert. 
Post removed 
It seems like you have a very good integrated, and that the power it provides for your speaker is more than adequate. Bass is so much a function of the room that I would strongly suspect that if subs and traps/treatments are off the table, you have only a couple options. One, would be to partially plug the port in your speaker. I did this with my Salks and got some additional control. Another would be biwiring or biamping the speakers. I've never done that but it could gain you additional control. A third option would be to play with placement. A final option is a much more powerful amp but, there, I'd bet that 10 to 1 that the amp does not help you get what you're looking for.