Magento - change left margin navigation menu Magento 1.9

Hi everybody, I need somebody to help me change the working of the left margin navigation menu of my Magento 1.9 store. Currently when you click on a category name that has sub-categories, it takes you to the category page associated with that category name. The only way to expand the menu and expose the sub-categories under it is to click on the small "+" to the right of that category name. I would like to modify this behavior, so that when you click on EITHER a category name that has sub categories, OR the "+" sign next to it, it expands the menu and exposes the sub categories under it. Thanks in advance... I am waiting for your bids or requests for additional information.