iPhone Backup File Location in Mac OS X

Ok, I'm trying to retrieve previous records of my Whatsapp chat history (because to my horror I only just realised that Whatsapp does not actually save your entire chat history - it only saves up to a certain file size limit). What I am trying to do is to restore my iphone from a backup and then access Whatsapp and email myself earlier records of my chat history. Once I'm done, I'll restore my iPhone from a backup created today so that I can get back on track with life.

To do that, I need to create a separate back up file (for the backup today) on top of the one I currently have in iTunes. However, problem is iTunes only allows you to create one back up file at any point in time, i.e. the back up I create today will overwrite the back up I currently have on iTunes.

I searched online and many say the solution is to copy and paste the back up file elsewhere. I've been trying to find the back up file but to no avail. Many say it's located at: "/Library/Application Support/MobileSync/Backup/", but I don't have MobileSync in my laptop.

I'm using Mac OS X Lion.

Thanks in advance folks!