I have a 12 yr old and a 5 yr old. My 12 yr old gets to stay home for 1.5 - 2 hours after school. Our office is about 10 minutes away. I dont think he is old enough to care for the 5 yr yet. If it was me I would stay home.
You have a lot of time to try and find some one else. Do any of your friends have older children that can come over and watch the little ones?
I hope it works out for you and you are able to go!!!