I have tried to enlarge your plans but they become to blurry to read.....Is there anyway that you can post a larger jpeg?

Let your wooden beam be as it is. put your Led lights in the other direction ( two on each side in one rectangle , so the total will be 16 units of say 10 watt each Led.), as to balance the horizontal and vertical shape. Don't put anything on the wooden beam to retain its the beauty.

that is what i have added if you can see the pic above.. want some suggestions on partition that i can use between dining and sitting

The living room window itself does not appear to be designed to let much light through. Please show a photo of that window, also of what lies outside the window. In the meantime, I suggest that you replace the builder-installed window with one of your own choosing. Use toughened glass rather than this heavy grill. Minimise the frame, if possible, particularly if there will not be much air coming through. If there is the potential of air but not much view, then have a sliding or bifold window that maximises the opening. On the blank wall outside, if that's your view, put up a green wall, creeper, something to improve the outlook. For nighttime viewing, add mild uplights in a natural white shade, focused on the greenery. Or else, you may be able to put up a reflective surface on the facing wall, to bounce in more of whatever light there is. Such as a coloured glass mural if not a plain mirror. Once you have maximised your window, move on to the wall to the right of your living room photo. That is, the wall that your living room shares with the west bedroom. Use a very large mirror on that wall to expand your living room visually and to bounce more light around. To cut down on expense/effort you can make it out of several standard-size sheets rather than one giant sheet. However, if that wall is to be covered with storage, make sure the front surface of the cabinetry is fairly light-coloured and reflective. Last, if not yet satisfied, consult a lighting expert for this room. That would be useful. These are fairly expensive solutions, all in all, but they should help.