Internet Speed problem

My internet is SBC Yahoo! DSL. 1.5mbps downs./384kpbs ups. its a dynamic ip. ummmm..... usually my download speed is around 150kbps which is really slow compared to other people's download speed....... and i thought it was because we were at different websites, but when we downloaded from the same website, one of my friends had 350kbps and another had 280kbps. is there anything i can do to fix this problem? because doesnt 1.5mbps mean my dl speed should be 1500kpbs?