There is no one site where all the acts (updated as to date) along with rules are available.
A few sites like AdvocateKhoj and Vakil No.1 do have a large collection of bare acts but they are not updated.
I would suggest you to visit the relevant ministry or department website for all latest acts/rules/circulars/notifications/clarifications.
For Instance, e-book of Companies Acts and Rules is available on Ministry of Corporate Affairs webstite.
Income Tax Act along with rules is available on Income Tax Department website whereas you can find SEBI regulations on SEBI's official website.
A few updated acts are available on Income Tax Department website but you won't find all relevant rules/circulars/notifications/clarifications there. Link- http://www.incometaxindia.gov.in/pages/acts/income-tax-act.aspx