buy it from GOVT approve breeding center. Mostly Swaminarayan Sanstha ( all are NGO ) have Gir Cows for sale see list of OCT 2013
http://dahd.nic.in/dahd/WriteReadData/GIR%20cattle%20available%20for%20sale%20OCT_2013.pdf
or go to this for gir cattle Ahmedabad-breeds
don't fool by any other...