How do I download and install a proposed ubuntu package from Launchpad? I am technical but not THAT technical so if you could give me a hint it would be much appreciated.

To give you a background on this, I am affected by a very annoying issue where my menus become unresponsive (see Unity menu very slow and unresponsive), and it happens on both my main machines -terrible bug if you ask me.
This issue renders Ubuntu unusable at times, and I've read on that same page that a fix might be available in the new gtk3 package (3.8.6).

many thanks