Downloaded the zipped fonts as well as the keyboard layout and started with copying the fonts to the fonts directory.
sudo nautilus fonts:
After this the keyboard layout needed to be edit with the new one which was obtained from below link.
Using this command I opened the layout file and copied the contents of ur.txt file present in ur.zip, obtained above.
sudo gedit /etc/X11/xkb/symbols/pk
After saving the changes adding Pakistan keyboard layout at System > Preferences > Layout did the trick. To place a shortcut with which I can easily switch between the layouts, I added Keyboard Indicator to the panel.