I can see the bind you are in, but you can afford a decent "formal" sporran. Check out these links:
Black Fur Dress Sporran
Brown Fur Dress Sporran
Gray Fur Dress Sporran
White Fur Dress Sporran

I bought a white one from somewhere with comparable prices that Stillwater has. I've worn it once just to wear it, and it probably won't be worn until Christmas time. But it is nice to have in case something formal does arise. Oh, and 3 weeks? Psh....Stillwater would have it to you in less than 3 days. ;)