Modifications to my oscommerce site

I have an OS Commerce site that has been modified to allow outside sellers sell their items after paying a subscription fee. I need to be able to see what a seller has posted to sell. I currently can not go into the admin section and see what a particular seller has posted to sell. I need to be able to look them up and see all of their inventory. I should be able to do this by their name and email address. I should also be able to pull up a particular item via the admin section and see what seller it belongs to. Also, when notification of an order/purchase comes to me (as a site owner/seller) or goes to an outside seller, I would like for the notification to show the picture of the item as well as the item description. Please let me know if you have questions. This may be confusing and I'm happy to clarify where needed.