You are most welcome dinesh
As regarding avr vs stereo amp. My suggestion is always avr first. But you will have to spend more to get a avr with pre-outs atleast for the front L&R speakers. This will give you the flexibility to add a stereo amp into the chain in future when funds allow.
Please always remember, that a good sounding system is a life long pursuit. And not one achievable instantly unless we win the lottery over night. So start with a well planned road map of where you want to be 5 years down. And be patient getting there. Rushing down that street leads to lots of boxes being brought and sold in the interim at a loss.
Coming to my first point, please start with a avr with atmos, atleast front 2 channel pre-outs for the front, two hdmi outs and atleast 2 subs outs. This will be expensive to start with, but will be economical in the long run. With the same consideration I bought a marantz SR6011 two years back. And I have added a lot to its pre-outs to take it to another level. And if you are patient enough, used avr's with the above facility will soon started cropping up in the 'for sale by owner ' section.
Next coming to speakers, there two things you need to clarify before we can decide. I can see that your width at 10 feet is limited. So your speakers will be close to side walls. So how much distance can you give them from the rear wall.
Also I see that the length of your room is 20ft. So how far back will be the listening chair. And its distance from the wall behind it. Iam asking this becuase if you have a wooden partition or wall close behind your listening position, there will be a piling up of bass there drowning out mid range detail.