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