Any cables that give more bass

Djtiti, The problem with using a loudspeaker with more bass extention in a room as small as yours is there is no way to control the bass. If you use a subwoofer you can control the level with a knob on the back. You can't do that with a full range loudspeaker unless it has built in subwoofers with eq and level control. Ideally you could get a sub with a eq built in for even more control. Jafox is right about using the pre out of the DK to the sub. I've done this before and it works just fine. I think a sub is the best way to go in that room.

Djtiti,
Matching the speaker’s output to a room can be as important as choosing the speaker itself. The interaction of room and speaker is crucial and often overlooked. Over time I’ve learned that a small-sized speaker in a small- to mid-sized room (like my own) can sound like a very large speaker in a very large room. On the other hand, a large speaker in a small room often sounds like.. ahem...crap most of the time. That is the reason why I am an advocate of small speakers+subwoofer in a smallish listening environment.

Placement of floorstanding speakers, either towers or bookshelf speakers on stands close to wall boundaries will often make the bass boomy, voices chesty and midrange colored. Imaging will suffer too. Although bass is stronger where the speaker is closer to the wall, more so towards the corner, the latter is the worst location for all other frequencies and this sort of situation has led to the popularity of subwoofers. They can be located where they produce best-sounding bass while smaller speakers can be located where they deliver the best sound and imaging for the bulk of the audible spectrum. Since subwoofers operate only at low frequencies of typically below 80Hz, they are very tolerant of where they are mounted as the wavelength radiates in all directions.

That brings in the question to the size of your main speakers, the KEF Ref 203. I've looked up that speaker and feel it's a relatively large speaker given the size of your room, and as said earlier was a little surprised that it didn't go lower than 55Hz given the size of the drivers and cabinet enclosure. If you really like the sound of your KEFs(as you have suggested in your last post), I would suggest keeping the speakers and getting a subwoofer to reinforce the bass if it's only the bass that did not live up to your expectations. It may be your DK Design amp, or it may be cables(as some have suggested) but if I were you I would follow the majority of forummers that have advised on getting a sub. You can end up burning more money on cables, unless you don't mind having a few pairs for evaluation purposes later. Good luck.

thank u all?since so many people recommended,will try to set it up tonight with sub!!!!

Kijanki, the lowest bass note is 44Hz on the electric bass only.
Acoustic bass / double bass / contrabass reaches 31 Hz and grand piano's lowest bass note is 27.5 Hz, clearly out of the frequency response of the OP's speakers.
http://en.wikipedia.org/wiki/Double_bass#Pitch
http://en.wikipedia.org/wiki/Piano_key_frequencies
Not to mention Oscar Peterson's favorite piano, the Bosendorfer...it does 16 Hz!

Personally, I would not mess with a subwoofer, they are difficult beasts to adjust and rarely if ever blend seamlessly with the main speakers. I would spend the money on a speaker upgrade.

Casouza - 31Hz is only on five string acoustic bass. I don't know how common they are in orchestral music but not very common in Jazz. It is often used in rock music (5 and 6 string bass guitar) but not for the purpose of the lowest note B=31Hz but for the ease of playing (same for the 6th string). The A=27.5 Hz on the piano i seldom used - just listen to recordings. I am not familiar with Oscar Peterson's piano but just cannot understand why they put non audible (16Hz) string on the instrument. 40Hz should cover at least 90% of music and I would rather go for bass performance than extension.

I'm not a musician but I'm just guessing that most of music is written for common instruments and would be difficult to find jazz composition that requires 5 string acoustic bass.
Isn't acoustic bass in orchestra a 4 string instrument? Any musicians here?