Build Materials Requirements Planning/Production Planning Tool

My company is a startup and we don't have the budget for massively expensive ERP/MRP systems like SAP, or to pay many thousands to get someone to set up a use case for open systems like OpenERP or ERPAG. I need someone to first build be a tool that I can use as a basic Materials Requirements Planning/Production Planning Tool, and then train me on how to use it (the training part will come during a second job I will create). I'm open to a variety of options (Excel, a set up of OpenERP or ERPAG), and I'm ok with workarounds that are analogous to what needs to happen (ex. treating processing of components as a component to make up a final product). I've attached a PDF with the basic Production Workflow that my company uses. Essential parts of the MRP/Production Planning tool are: • A BOM (Bill of Materials) • Materials/component inventory tracking and planning as they get integrated into a finished product (see attached diagram) • Production schedule informed by a sales forecast and based on lead time for production of the various inputs, Minimum Order Quantity of the various inputs, and other elements that are considered a standard part of a MRP/Production Planning methodology. • The MRP/Production Planning tool must contain at least one example showing how the basic Production Workflow requirements are met (components being assembled into a final product and all related elements tracked - based on the attached diagram) The tool must be completed within the budget constraints of this job - so you have one week at a max of 20 hours worked to create it. If you successfully complete the project I will be happy to open a new project and re-hire you to give me more in-depth training on how to use it. But the basic functionality in the tool must be intuitive and able to be used without training.