As Roland told you in the other place where you asked this ( http://forums.creativecow.net/thread/2/1046998 ), there are plenty of resources about this if you do a search.
See this page for resources about making After Effects work faster: http://adobe.ly/eV2zE7
See this page for information about hardware for After Effects: http://adobe.ly/pRYOuk
One thing that leaps out immediately is that your computer barely meets the minimum system requirements for After Effects. Get more RAM. Then follow the other guidance in the resources that I linked to.