Create an App for iPad / iPhone / Android -- 2

I want to create an app. At this stage it is very early stages, it may not happen this month but it will happen. This is part of a larger program that I am developing. This app is just a taster for the larger program. I just need rough idea of pricing at this stage so we can budget for it. I'll need to see proof of previous work with process type apps. Specific details will follow once successful partner is awarded. This is a very rough overview. It's a time management / getting things done / to do list sytem. There will be multiple lists. Users have ability to add as many lists as they want. There are 3 main lists. First list is the main list (Broken into categories - customised to suit the user. Categories can be colour coded). Whenever a new task is entered, it's automatically entered onto the main list. This list will have a name that is permanent and can't be changed. Then there is List 2 and List 3. These 2 lists will also have permanent names that can't be changed. When you enter a new task, needs to have various options pop up. Can edit the parameters of any tasks within program with the push of button. Various sorting options. Sort by priority, date, etc Adjust the order of tasks manually. Easily create new task with one tap of a button Each task has a check box. Once task/s is checked. Options below say Move to another list, Complete. Ability to select multiple tasks at once from any list and move them to List 2 or List 3 easily. I need an idea of pricing. It's not about the cheapest. It's about getting the job done quickly and according to the specs. It's also has to allow for changes and alterations once we start using the program and realise little bugs to be fixed up. As I said more detailed specs will follow with diagrams about the look and feel of the app as well once the successful bidder is selected.