Both are huge needs. I don't know that you can do both in a cap era though.
Whichever one we can fill most effectively at the right price, Bergevin needs to pull the trigger on.
Chicago won without a good #2 C (Bolland, Handzus and the ghost of Brad Richards were the #2s on their three cup teams). Pittsburgh won with Letang and no #2 defenceman. This league is all about filling as many holes as you can, coaching players to be adequate in the roles you can't fill, and hoping for the right matchup so you can hide weakness and exploit strength come playoff time.
I don't know which hole we can fill... but if Price is playing well, my inclination is that #2 C is more important, and that Carey will make up for defensive deficiency if you score enough.