Orange/Brassy Hair HELP!

You need a color with a blue base.  You can get that at a beauty supply shop and will have to buy developer to go with.  If you choose a color with a blue base that's about the same shade as you have (and want) you should be okay.  But still, do test strands to make sure you get the timing right so nothing gets a bluish or greenish tint.  It looks like the hair in the front is slightly less orange so be sure to test strand any places that may be a little different in color from other places because if any of it is yellow, it will come out green (violet based dyes counter yellow).  You can't tell what base is in boxed colors, so if you don't want to fool with this (which may or may not be tricky) go to a salon and let them do it.

(Note: I'm not a pro).