Help me with my hair!!!!!?

listen guys i want to colour my hair from brown to blonde but i dunt want to colour them completely.I want the style that JANE(ashley olsen) has in new york minute.Half blonde and half brown.If u have seen the movie u will know what m talking about.Please tell me how to i get it??????or u can also check out hayden pannetiere for that type of style which i want but NY minute is the xact one.