Blackberry app - timeline/date calculator

I am seeking quotes from developers who would be interested in working on a Blackberry app. I am told it would be a simple algorithm and accordingly I am setting the budget at $500. The app would enable users to produce a timeline by inputting a single date and selecting a few other options. The calculation would be the same each time. Only working days are relevant. This means no weekend dates and certain other specified non-working days (these are published annually). We can discuss the design separately and I can provide a mock-up of potential display formats. Look forward to hearing from you. Thanks, GM