I am a bit confused about your GarageBand version, what is it?
"Garageband 1.1". or "latest GarageBand version" or "GarageBand '11" as in your signature?
If you really are having the latest version GarageBand version 10.0.1, you can download the additional contents by choosing "Download More Sounds" from the GarageBand menu. That is a paid in-app purchase. If you previously purchased this content, select "Restore Purchase" to install the content.
See this page:
In the United States it is $ 4.99
GarageBand for Mac (v10.0) is available free on every new Mac and as a free download on the Mac App Store for all OS X Mavericks users. It comes with the full set of features and a great set of starter content including 50 Sounds, 500 Loops, 1 Drummer, and 2 Basic Lessons for Guitar and Piano. With a one-time in-app purchase of $4.99, you can expand this content to 200 sounds, 2,000 loops, 15 Drummers, and 40 guitar and piano Basic Lessons. You will also gain the ability to purchase additional Artist Lessons.