Where I work, "business casual" is pretty lax...non-jeans that reach the top of the shoes :rollseyes:, any top that is not sleeveless and covers the midriff, and closed-toed shoes (though we're permitted sneakers). I guess "business dress" is "anything fancier than that."
Though, I'm lucky...I get to wear scrubs if I feel like it. :D
I'd say get a pair of closed-toed shoes if nothing else.