To add a shared windows printer:
1. Go To, 'System Preferences' -> 'Printers & Scanners' then click the lock to make changes, enter your username and password.
2. Click the '+' sign then select 'Add Printer or Scanner....' right click the tool bar at the top and select 'Customise Toolbar'.
3. Drag the 'Advanced' icon that looks like a cog up to the tool bar.
4. Click 'Done'.
5. Click the 'Type' drop down box and select 'Windows printer via spoolss'.
6. Enter the address of the printer as smb://servername/printername
7. Click the Use drop down box and select 'Select Software...', if your printer is in the list choose it if not download the drivers from manufactures site, if it does not prompt you to install the printer only installs the software it will put the drivers in the '/Library' folder somewhere in the Drive Root.
8. If your printer is shown, click 'Add', like below.