speaker placement, room treatment esp. floor ?

so i've sorta-kinda settled in to my new apartment, it's a 'loft' style place, considered a 1 bedroom, although i'd call it more of a glorified 'studio' because of it's open design.

anyhow, i'm struggling w/ the concrete floors, my old place was built in the 1800s and everything had a warmer, richer sound (part of it might be because i was closer to the speakers and the back wall?). anyway, what i see is, by math, the room is pretty decent, 13-14ish foot ceilings, 23x18, so no 'factor of' stuff going on... however, it's my guess that between the ceiling design (open LARGE wooden rafters), the concrete floor, the brick wall on one side and open wall on the other and irregular rear wall, well, lets just say i'm guessing it's all adding up to skew things.

my apartment layout - http://www.dmoffitt.net/apt/apt_layout.jpg

now. a few words before getting deeper into my questions:

my rig is 'good mid fi' or 'cheap / low-end hi-fi' at best. i'm a 24-year-old finishing my BFA degree in Film & Animation who got into hi-fi because of my love of movies. lately, HT has taken a back seat to 2chan. listening, ever since i purchased my CDM-1 NTs. now, i know they aren't the end-all-be-all, not even CLOSE, but upgrading from DM602 ser.1's to these, well, i'm happier. a friend has a pair of Totel Acoustic's Model 1 sig's and i'd say the B&Ws are about, oh, 80-90% of what those are, they don't extend as far down in the lower bass range, and the highs are still too bright/forward compared to the Totems (or 'better' B&Ws such as the 803/804).

anyhow, my rig in a nutshell:

Source: Apple G5 via AudioQuest OptiLink-1 digital optical cable (12m)
OR sometimes, Rotel RDV-1060 (for DVD-A / or sometimes redbook cd)
California Audio Labs Sigma (tube) DAC
Rotel RSX-1055 (using it as a Pre and to power my rear/surrounds)
Rotel RB-985 5ch amp (2ch each per fronts, last ch. is for the center)
all analog ICs are AudioQuest Coral (1m)
CDM1 NT connected via 2 runs AudioQuest CV-6 (Bi-Amp cfg)
CDMC NT center / DM600 ser.3 rear/surrounds (7.x setup)
Misc: StudioTech rack & stands (stands are filled w/ sand. they're CRAP tho, but i can't afford much more right now, hoping to find a sub-$300 upgrade). Panamax 5300 power conditioner, amp hooked straight to the wall to hospital grade outlet (audio rig is on it's own circuit in the breaker, thank god the apt. builders knew what they were doing!). Oh, and if it matters, a 32" Hitachi plasma (forgot the model, about 1-1.5 yrs old).

Back to business - so, for movies it's quite good, but as i've been told and guessed myself, that's the EASY part. could DEF. use a subwoofer, i'm hoping to audition an SPL 800, SPL 1000 and Digital Drive 10 (12?) in the near future, but i'm trying to optimize everything else to a reasonable extent before re-complicating stuff :)

But music, while extremely detailed, accurate, and with a VERY wide and fairly deep soundstage, lacks a LOT of bass, and the midrage could be a bit more forward or rather, like, warmer / more prevalant (which is funny to say, as the reviews I read years back of the CDM-1 said they midrange was a touch TOO forward, maybe it's my ears?). So what can I do to improve the low-end re: placement of the speakers, room treatment, furniture, etc? this afternoon I'm heading to home depot to snag a piece of 12x16 ft carpet to try and help things, i noticed a HUGE improvement just putting a 5x7 ft one between my listening position and the front / speakers, so I figured I'd see if I could further that (my guess is it cut down on the overwhelming reflections etc).

Also, with the concrete floors, do you think any of those subs will work or will the concrete make everything 'boomy' or peaky (hence considering the extra $$$ for the DD, being able to tune around room freq. problems)?

currently, everything is spiked directly to the floor (except, the rack's spikes are on brass 'cups' to help facilitate moving when/if necessary. the surrounds are hung on the wall (but as i said HT sounds fine).

I realize iv'e got a lot of areas that could use addressing re: equipment (i really want a good tube pre for 2ch, and a nice big 2ch amp like a b&k, classe, krell, etc) but right now, my budget allows only smaller occasional expenditures (except MAYBE the sub)... spending $90-150 on carpet vs $3-4000 for amplification, etc ;)

btw, to help picture the room / predicament better:

my apartment looking from the outer wall in (not my apt. actually, the neighbors, a mirror-image L-R of mine) - http://www.dmoffitt.net/apt/apt_looking_in.jpg

looking out from the kitchen area (again, not my apt.) - http://www.dmoffitt.net/apt/apt_looking_out.jpg

i've tried placing pro studio foam (same as we use @ RIT) in various places, to little/no improvement (either my ear is untrained or i've got bigger fish to fry, or, likely, both).

i do realize this will never have that jaw-dropping kind of sound that many of the rigs i've read about here have, but i'm VERY VERY happy with it, i just want some ideas / tweaks / direction before I start going and selling stuff a lot, spending money etc (ie. i want to get the most of what i have). my EVENTUAL plan is that this will become my films-only rig and i'm in the process of planning a 2ch only 2nd rig, but for now, budget, space, etc. dictates a 'hybrid' movie/music setup :(