190253 Database, inventory control

Due to inventory control issues, I need to work out the average rate of sale of all my products. I have all the data - but do not know how to convert it. Data I have: *1 year's worth of completed orders (in the format of items sold - please see attachment for example. The ACTUAL list is much longer). *1 year's worth of sold items which can be found in my inventory control system which is OptionCart (see [login to view URL] to see a demo site AND admin). It can be found under "sales" in the user admin. You will have access to my websites cPanel if you need to access the mysql database. What I also need to know (within the one year period 2007) is the date the product sold for the first time, and when it sold for the last time. That is due to the fact the item may have only come in stock in July, and sold out in September (FOR Example). So the average would have to be taken over a 3 month period, not the whole year. And from that data, taking into account the day the item first sold to the day the item last sold, I need to know the average number sold per week. Extra info: I have around 2000 products total. I don't know if this is actually possible from my data sources. Please PM me to discuss if you have any questions or suggestions.