Costg of extension to side and rear of house

dbyrne

I am looking to build an extension on the side of the house. I havnt set down with an architect yet just asked the wife what she would like (big mistake):D. Answers are as follows
1 story kitchen to rear, 3 - 4 large velux windows to roof
2 story extension to the side of house with downstairs room, part of extension to kitchen and upstairs 2 rooms with 1 ensuite between rooms. roof of house to be extended over new extension, 2 velux in attic and floored

I was wondering what sort of budget would you need to build this extension.(again like many posts its the how long is a piece of string approach)
Would it be cheaper to buy it in maybe a kit form and get it erected? e.g .premade walls in factory?

to explain picture, sizes given are (wishfull) ideas of what i would like.
Red is new extention details
Orange is what is to be removed to make big open plan kitchen (outside wall of house downstairs)
yellow is some existing house measurements

I understand without more information of finish etc it is difficult but what would I be talking about.
I am talking
- walls and roof
- windows and doors
- insulate walls and attic
- plaster
- plumb and wire
- skirting boards on
- concrete floor ready to lay tiles on.
- solar, boiler, rads etc

There is no point in asking to include kitchen, sinks, showers for ensuite in quote as they are personal taste and you can spend 5k on a kitchen or you could spend 20k on a kitchen

Thanks in advance.