Curry leave freeze very well, so you can easily buy a bunch and freeze some for later. I have also seen them for sale dried, but they loose a lot of flavor that way. It's an easy thing to grow, BTW, if you're in a warm climate. Mine has even withstood a bit of frost.

Thanks again for everyone's advice and research...the dish turned out pretty well without the curry leaves, with basil instead. But tomorrow I will purchase curry leaves at a different market and attempt the recipe again. :)

You can find curry leaves in America The Asian Grocery Store Demystified (Take It with You Guides) http://books.google.co.in/books?id=MnsRP1cOqisC&pg=PA32&lpg=PA32&dq=linda+bladholm+curry+leaves&source=bl&ots=7Gnrc0j2un&sig=wBva-i9zNKDTNj0qMGAf1ZG_hO0&hl=en&ei=QgWxTMvKAc6HcYaeuecN&sa=X&oi=book_result&ct=result&resnum=5&ved=0CCMQ6AEwBA

I'm glad you got all this good advice in time to make your recipe. Just wanted to add that if you ever do find the curry leaves, make the recipe again. They are so amazingly fragrant and lovely. I've found them at my local organic (co-op type) market as well as at specialty and Indian markets.

curry powder is a combination of spices like dry coriander powder, chili powder, turmeric powder and other spices like cinnamon ,black pepper etc.
And curry leaf http://en.wikipedia.org/wiki/Curry_Tree is a herb like rosemary thyme
If you don’t have curry leaf do the recipe without it, curry leaf is not a substitute for curry powder.

thank you so much! I was just about to add the curry powder but now I'll remove it from the recipe!

No, curry powder is not a substitute. Curry leaves are an herb,not spices like curry powder. There is not a real substitute if you can't find them fresh or dried at an Indian Market (they won't be in a regular market.) You can just leave them out of the recipe or use another herb. I read that basil may be used.