How can I in Lync 2013:
1) Set status of Lync 2013 user?
2) Extend the popup menu (when I right click a user)?
For your second question, just follow the instructions given on the following web page: http://msdn.microsoft.com/en-us/library/office/jj945535%28v=office.15%29.aspx.
Only the registry entry paths given for 32 bit and 64 bit are swapped i.e. for 32 bit use the 64 bit path.
Regarding your first question, how exactly do you want to set the status? Through code or just add a custom status message.