Hi, how do i add another one, lets say swap with another one?

item.php or category.php look for the toolbar code

any information on this?

You need to edit your item.php file for single items or your category_item.php for items in category listings.
This tutorial will help you locate these files and/or create new overrides.

Then search you code for something like facebook or fb to locate the social sharing buttons and paste the code of your button. You can use any markup you want for this button.

Finally apply some CSS to the new button (like float: left).