software program converted to web

I have a software program that is currently written in MS access. I was speaking with a developer who told me this program could be converted to a web application and make it so we can add functionality to it. I am looking for someone who understands this process and can also add more features once the program is converted. Please explain how many hours you feel this would take when bidding. It is my understanding that there are programs on the market that assist in the process.