Adding Instagram or additional Social Links

Ok I’m still having trouble adding additional social links like Instagram which isn’t part of the list you have. Right now you have Facebook, Google +, RSS Twitter, Pinterest, LinkedIn, and Skype. I’m wanting to add in Instagram and perhaps Tumblr but right now I’ve had to use the Pinterest as “Youtube” and just change the pinterest icons to be Youtube ones.

My client will be asking for the other ones and I’m running out of room. I’ve looked through the widgets.php and I don’t see where to add additional social links.

thanks