Excel 2007 : Formulae required for a stock report

Hi

I need to create formulaes for a spreadsheet to give me the detail below:-

Column A is 50
Column B is O.5 current stock coverage what column A equates to
Column B is 21/04/2009 (todays date)
Column C is 2.5 is stock coverage I need to have at any given time.
Column D is stock on order
Column E is what I need to order to reach 2.5 (formulae required)
Column F is (formulae required) date I will be at 2.5.

Sorry new to the forum, hope I have explained appropriately.