there are many pros here who can offer you great advice from experience,,,
i'm only chiming in cos i have a 003,but my order of purchase was.
firepod...thats how i started
mics <nt1a 2xsm81 sm58 akg d112 etc> untill i felt i had a set that i could work with
003 -upgrade from firepod
focusrite octopre, gives me 12 ins in total.
the next purhase for you depends entirely on your needs...
if you have bad vocal recordings,,,maybe invest in a nice vocal mic,
but one thing that people always said to me was
dont upgrade thinking it will make your mixes sound better.......upgrade because you've fulfilled the potential of your gear..
i don't know your current abilites and skills,,but time invested with what you have is much better than money invested in gear you might not use to it's full potential.
hope that helps
