Newbie question about costs?

Hey guys i'm looking and building a studio next to my house and was interested in know if anyone would have any idea of the cost of building a small studio designed similiar to http://www.saecollege.de/reference_material/index.html the corner control room. but instead of the Kitchen and studio B it's 2 smaller vocal/iso rooms. The exterior walls would be 7m X 7m max here is a sketch up of the idea. I would need to build everything from scratch. The concrete base up. and i would have to be fully sound proof as there are neighours near by. cheers