you can get a toner from farmers, it's called Schwarzkopf Nordic blonde toner. After you rinse your hair, before you condition apply some of this, leave on for a few minutes (not too long though otherwise you will end up with purple hair!) Gets rid of all the unwanted yellow and ginger tones 

 After a bad experience at the hairdressers a couple of months back I bleach my own hair and this stuff works wonders and you can only imagine the tones I get from home bleach

 and yeah go for the full length of time!