Converting Excel to Web-Application

I have an Excel-based deal valuation and marketing program. Nothing too complicated. I am looking to convert this to a web-based application. The developer must have solid math skills as the project will require transferring the underlying math formulas and architecture from Excel to the web. In addition to simply replicating the Excel program in a web-based environment, the new website will need to have a database behind it able to store various user's login credentials, deal information and pictures, and other info. There will also need to be multiple membership levels and levels of access to various features of the website. This can be quoted separately as "Phase II" but the underlying platform must be able to accomodate this. Please reply with your credentials, samples of your work and experience, and contact info. I will then provide more details about the project.