If you put a lot of dye, your hair will stain purple. You want to keep the purple fairly light or just buy a silverizing shampoo which you can leave on for a bit.
As for the bleach, that will depend on wether the orange is from the previous dye or just your natural undertone. It is difficult to say at this point. You can do a strand test to see how light it will go.
Bleaching out dye always creates much more unnatural orange tones than bleaching natural hair. If you decide to go lighter definitely do the colour remover first, it will be easier in the long run.
Ok, thank you both for your help! I'll update once I've tried the purple conditioner. π
Oh, another question. How long would I leave it on?