Seting up network interfaces can be tricky!
I would scrap all the work you have done so far and do this (5 Minute Fix)...
I'm guessing by the router you listed, you have Vodafone Internet, if so here is a quick guide for static IP Address on that model..
Log into your router in basic mode:
http://192.168.1.1
username: vodafone
password: vodafone
On the left panel under "home network", click on "connected equipment" and locate the device that you want to give static IP address to..
Hover the mouse over that devices current IP Address and the MAC Address will pop up. Write this down..
Now also on the left panel select "router" then "Lan", at the bottom of this page you have a section called "List of reserved IP addresse"
You have these three box's to fill in:
Name ------ IP address ------ MAC address(e.g. 00:12:1F:E1:3F:3F)
The name Is whatever you want to name the Static IP Reservation. e.g. UbuntuServer
The IP Address is whatever IP Address you want to give the device permanently.
The MAC Address, you got above /\ /\
Once you have filled in all of these click Save & Reboot.
That restarts your router with this rule activated. Now restart your device and thats it, you have a Static IP within your Local network..
