Add facebook to oscommerce

Need a feature on a oscommerce store where user be able to share on facebook any article. Same store has a bug when adding an article, if user is not registered, after registration item is not added in the basket, and when adding that article there are two in the basket. Need to change link, insted of create account, when user is logged the link must be -my account-. Contact us and Search result have a bug in displaying categories. Categories are being displayed expanded and must be collapsed. Please write a PM to let you know the URL so you can place a proper bid