Please help

I am new here and desperate.  I had blonde hair (color treated) for a year which had become too platinum.  I needed to warm it up for winter and bc it was too white for my skin tone.  I consulted a few websites and determined that i should go with a medium blonde as it wasn't too far off from the light blonde.  i used feria medium blonde/blonde chiffon.  i noticed a slight improvement but only on parts of my hair.  i then applied feria caramel twist, assuming i needed a darker shade for it to take.  i now have purple hair.  i cannot afford to go to a salon at the moment and even worse, i have an event to attend this weekend!  i was thinking of using the ion crystal clarifying treatment sold at sally's but don't want to make anything worse!  this just happened yesterday.  please.....if anyone can help me i would so appreciate it!