This site will have what you need.
http://gosouthamerica.about.com/library/blSamaps3a.htm
I need a detailed map of south america, showing were the Andes Moutains, the Central plains, the Eastern Highlands and the equater.
2 answers
The Central Plains are sometimes called the Gran Chaco. The Eastern Highlands are also called the Brazilian Highlands. Check these maps.
http://www.lib.utexas.edu/maps/americas/south_america_ref04.jpg
http://www.graphicmaps.com/webimage/countrys/salnd.htm
http://www.lib.utexas.edu/maps/americas/south_america_ref04.jpg
http://www.graphicmaps.com/webimage/countrys/salnd.htm