Hey Gowtham -
You can certainly do the first part (filter by year). You may be able to get the second part done depending on your report format and what your expectations are.
For "Part 1", simply add a filter to your command-line when you request the report. For example:
tabcmd export "Sales/Sales_Analysis" --pdf -f "C:\Tableau_Workbooks\Weekly-Reports"
tabcmd export "Sales/Sales_Analysis?Year=2011,2012" --pdf -f "C:\Tableau_Workbooks\Weekly-Reports"
This assumes you have a dimension named "Year" in your data source.
For "Part 2", you should investigate using the Pages Shelf
Hope this helps!