Calculator app and software

I need an app created which calculates the amount of time that someone has possession of a product for. The best example I can give right now: let's say that you and I share a vacation house. I get the house every other weekend, friday to monday, plus everything wednesday, plus 7 holidays per year, plus half of a school summer break, etc. The calculator needs to tell me how many days I have the house and what % of the year that is, and how many days you have the house and what % of the year that is. Users can either input the days by pushing the calculator buttons (which will be the days of the week and the weekends and additional vacation time) or click on a calendar and select the days over the course of 2-4 weeks (and the app should then continue the same schedule for the entire year). This will be used for a specific purpose which I will tell you upon acceptance of your bid. I need an app created for iphone/ipad and then perhaps android and blackberry. I would also like to have a version available for use on PC and Mac. I want the option to charge a one-time price or a monthly or yearly price. Must integrate advertising and also have the option to charge more for an ad-free version. For the PC/Mac software, I will need a simple landing page with checkout process. I previously hired someone who disappeared before finishing the project. I have a beta version of this app done already, but apple did not approve it because the programmer did not make it look nice enough. You can try to build off what he did, or start over.