Dear Mayank
1. The cost of construction is based on the plan ,elevation and specification used in the construction of building. For example the cost of basement is very less than ground, cost is also co related with types of foundation. For accurate costing you can e-mail at support@gharexpert.com for detail estimate.See the link below.
http://www.gharexpert.com/Estimator/detailed_cost_estimate.aspx
2. Please contact local architect of your city, who is well known to the rules and regulation of the cocerned department.
3. These works are well done by local person.