If you think the Chinese vase at the base of the table may be valuable, you should take it (or the photos of it) to a reliable art and antiques appraiser in your area. You aren't likely to get a reliable appraisal on line.

In USA and Canada, when the water table is that high...we are not allowed to dig basements past a certain depth (local ordinances make it illegal). Look to your local building codes. Hire an engineer and then think about living without a basement if you don't have much luck on solving this. If the water table is that high, you may have to look at earth stabilization techniques to protect against liquefaction during an earthquake. If you are in the rainy season, you may have to wait until the dry season to excavate a "half" basement (only a few feet below ground and the house has a raised basement).

coming to the dining area..yes id say you remove the seating entirely and concentrate on a foyer area since you already have space for a drawing room on the floor.. id suggest erecting a glass and marble wall in line with the wall that runs between the pooja room and the bedroom..say a bit of marble-glass-marble-glass-marble.in this case you have a small foyer area demarcated by this wall feature.you can deck it up by placing a nice console table in front of the central marble wall with a nice mirror to reflect the space and make it look larger or a sculpture with beautiful bracket lights on either side to accentuate the same.and on the backside of this wall you could have a crockery unit with a huge painting or a cluster of family snaps above it. if you could brief me a little on the look you're adapting for your house i could suggest some more treatments for the walls.if you want to avoid using too much marble you could also opt for a marble wood and glass look where you could take out some concealed storage for shoes etc. regarding the drawing room - what about a huge 4 seater in the center instead of 2 - two seaters with a table in the middle as in the plan..if you remove the central coffee table maybe you could replace the single seater with a chaise for 2 and also replace the 2 center tables with a nice long table in the center with an area rug running below it..if you could help me with the room dimensions maybe we could add 2 pouffes in front of the 4 seater so it creates more seating and doesnt obstruct the view if you plan to put a TV on the wall. what look do you have in mind for your terrace garden ? something zen or a little rustic toeing on the lines of the contemporary ? sorry for the late reply as i was travelling.. hope this helps! :)

I wouls get rid of 1/2 the pillows on the sofa too matchy add an area rug that is bright with some other colors to use for accents you have IMO too much brown so I would do blue drapes in the DR take the cloth off the table and add a blue and orange glass bowl for a centerpiece filled with green apples get some pillows in green and orange and a big piece of art work for the wall above the sofa and maybe a mirror on the DR wall and a fabulous light fixture for the DR an arc lamp behind the sofa in the corner so it comes out far enough into the room to light a coffee table.