Welcome to the club! Sounds like you're going to enjoy your iS - they're great cars.
No power to the turn signals seems like a fuse to me. Check the fuse itself for a hairline crack, and be sure the contacts inside the fusebox aren't burned or damaged. Occasionally the fusebox itself will melt a bit, causing some issues.
Do you have the electrical troubleshooting manual yet? BMW wrote it up for mechanics - it makes troubleshooting very easy.