Software Programmer

I have an MS Excel file that uses time value of money (PV, FV, PMT, etc.) to calculate various methods to pay down debts. The Excel file is complete, but I need a programmer to create a software that I can load on my company webpage behind a membership area, so only paying members have access to the software. I am not sure what type of programming this would be... although I assume Ruby on Rails with a database. The user would enter the list of their debts (credit card, car can, etc.), how much they owe, their interest rate, etc. then the formulas I have in Excel would show them their payoff schedule using various payoff methods. When the customer comes back after leaving the website, their information would still be loaded for them, but of course it must be secure since it is private data.