Most exhaust shops can fabricate a cat-back for you for less than $500.
I had a full cat-back done for around $455.
Don't mess with headers. The stock ones flow plenty well for most applications. If you have emissions testing, don't touch the cats. As for the muffler, you need to head over to YouTube, and see what you like the best.
I can suggest Thrush chambered mufflers. They are only $30 each and have a deep, throaty sound to them.
You want a 2 1/4" offset-inlet/offset-outlet mufflers.