So you like purple? Please buy soft lavender curtains, or some with purple printed flowers, I've had dark purple curtains in my old house (3meter high ceilings) and it looks really dark when they're closed. Add a purple sofa or lots of purple accents to keep it calm and friendly. You could paint the window wall a deep eggplant (not the other walls because of light) with creamy curtains.

Embrace the arches and keep it light, but add some contrast. Paint every wall with an arch in it fresh white, all ceilings too. Paint the adjecent walls a soft color. For example; when you keep the kitchen tile, you could paint the walls above it a soft pink or mauve. I see three open areas, so you could divide those with three soft colors and white inbetween. Keep most lights simple and functional, uplights will enhance the arches, glass pendants will add warmth. And I think a soft olive or sage green is a great color for a living room.

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 design is ok. On first look, the space around sink is a bit less, you may have trouble keeping dishes after washing. But that could be due to layout. It is a small kitchen. I prefer ceiling height cabinets to avoid dust gathering dead space. Even space above the fridge may have cabinet to store rarely used pieces of crockery. Chimney with its exhaust pipe is a must, not an afterthought. Consider under-cabinet light for workspace lighting; essential in my opinion. I also recommend lighter color of cabinets for this space. Too dark is too dingy, looks cheap and requires more maintenance. But that’s just my opinion. Have fun!