The Garritan Instruments for Finale (GIFF) collection comes with Finale and is a subset compiled from the various Garritan Libraries. If you loaded the demo before purchasing the Finale program, you would have had to reinstall the program to add the Garritan instruments. Beyond that, you have to purchase the GPO, JABB, COMB, GWI, etc. separately to use the full packages.

PrintMusic can use purchased Garritan libraries but does not come with them.

http://www.finalemusic.com/products/compare-finale-products/

GPO is pretty good for $149.