Try to get forgotten bow pink, lvl 15 (as you said). Also, try out this build:
6 rage
1 super mega slash
6 stomp
1 crippling slash (15 build). Get expert leather because it has a higher crit chance. With your crit higher, it is more easy for you to kill people faster. Try to figure out your ranges, if you master that, you will be a tough one to beat