Mac OS X Lion 10.7.4 Memory Help !

Hi my name is sebastian and iwe got a Mac as anyone could figure out and i got So little GB in memory i just cleaned my mac and recovered about 30-40 GB but i still have 160,11 GB Busy And i got so little files that i Downloaded i checked myfiles Memory use and all them togheter is about 26-29 Gb ? Please help me i really hate this because my memory just dissapears qucik as **** and my mac get ****** slow ...