Query on service tax chargeable on works contracts

Sir/Madam,

I am living in Co-Op Housing Society Ltd. My society wishes to carry out Renovation/Repair Work of tiles, painting ,replacement of pipes and other civil works.The Total Contract Value is Rs. 35 lacs. The material cost is Rs. 18 lacs and VAT Paid will be Rs. 2 lacs.The Contractor is a Propreitory Concern. 

What will be Service Tax charge on us ? Whether Rule 2A Option I is beneficial or Option II is beneficial ??? Whether in Option I and II CENVAT Credit is available or not ?

Please forward Calculation under both the Options.

Chandresh Sheth