I have developed life insurance software in Delphi 5 using ms Sql server 2008r2 in 2010 and used at 3 insurance companies. Most of the business logic are in Sql stored procedure and data modules.

I have developed life insurance software in Delphi 5 using ms Sql server 2008r2 in 2010 and used at 3 insurance companies. Most of the business logic are in Sql stored procedure and data modules.
Now I wanted to change the architect to make it future proof and easily deployable and maintainable. At present the problem is customer has to install at hundreds of client machines scattered geographically connecting to DB server using low bandwidth.
So can any body suggest me the best option available in Delphi to handle this issue. I am exploring thin client , intraweb , multi tier etc. please advise me.