Material Requirements Planning simple system.

I need a Software for Material Requirements Planning. I should be able to add new components, like DVD-RW, or a Motherboard, that could be simple i.e. a RAM Module or complex, i.e. a MotherBoard with RAM Module and CPU already installed. Any element could be simple and doesn´t contain other element or complex and contain others inside. I should be able to define the necessary time required for a construction, i.e. for the Motherboard for Students 1 day, RAM Module 0 days, also I should be able to define the time required for a component to be deliver in case I don't have it currently in the inventory. The software should be able to define if a client ask me for a PC for students, to save the structure (components simple or complex that it contains), but also the required time for assembly including the wait until the parts are deliver, i.e. according to the PC required it is necessary 4 days, 3 for the parts to arrive and 1 to assembly. Also important is that every component could be a sub component, i.e. PC for Student, containst Monitor, System Unit, Keyboard and Mouse, Basic School Package, contains 10 PC for Student and 1 Server PC. The times should be calculated using the MRP metodology, MRP requires a deliver date, the date should be today, determine the beggining date and calculate the difference in days, and display something like "7 Days required for production". It should have a module to handle the inventory, add, edit and remove products, those products will be my components, therefore they could be simple or complex, if complex I could be able to select products already in the inventory as components. I should be able to see and print the inventory, no need to look good just work. It should have another module where I could add any number of products, 3 PC for Student, 1 Server PC, it will be one manufacture order and the software should be able to estimate the necessary number of days to satisfy the entire production and every component, and should display a list where I could be ble to see every component I put on the manufacture list and how much until it is completed. It should have another module where I could see and print the components and the dates I should order them to my suppliers (buying orders), and also the dates where the components should be ensambled (production orders), but also if I order 1 PC for student and 1 PC for Small Office in the same order it should see if they are any common components and display them one time only on the list of the parts I should buy with the dates. It should check with the inventory i.e. I need 4 RAMs of the same model, it should review the inventory and see that I have 2 and my security inventory is one, therefore I should order 2, 1 to complete production and 1 more to mantain my security inventory, it should display both options. Order 1 to fullfil production, order 2 to fullfil production and mantain security inventory. It is a really simple project, and it will be 3 parts, this is the first time if I like the product, the timing and the price, I would repeat with the same freelancer for the other 2. I would prefer a more interactive process, if any doubt don't hesitate to contact me.