Four Concrete walls .... Studio from hell. NEED HELP!!

Hello all. Heres my situation. I live in an apartment that is typical bungalo divided in half. In my half they had built on kitchen. Under the kitchen is a seperated self contained basement. The dimensions are 10ft-6in. by 16 ft. The ceiling 8 ft high. You access this room from a hatch in the floor and via ladder. Me and the boys do a lot of jamming in this room and yes.. I do some recording in there too. So its four concrete wall and a concrete floor. The ceiling is vinly floor, plywood, wood flooring and joists. You can understand what kind of ugly boomy sound I get. Some people have asked me to record their bands and some solo artists too. I have some modest recording gear. My question, is there anything I can do to this room thats non-permanent, and on a very limited budget that will at least get a little boom out of the room? Any help would be muchly appreciated.

Raoul - click on the John Sayers Productions logo and check out "Wall Units" there a various free-standing absorbers you could consider. cheers john

Here is my tentative layout for my very small, hole in the floor studio. Any glaring problems? Muchly appreciated

Opps .. here maybe..