other posters have it right, salons and mall makeup counters, but be prepared to try a few before finding someone who really fits your style and budget. A really good MUA can absolutely help make or break a shoot from the vibe on set to the finished product.
Bonus Handy hint: try salons first because even though all MUA's will tell you they do hair, you want to find one that actually can.
Triple bonus handy hint: The good ones want to get paid. A lot of models will find an extra hundred/hundred and fifty bucks for a couple of hours with real hair and makeup even when the shoot is TFP with you. If you're building a book and your site a good MUA is in-freaking-dispensable.
so-so pics but fabulous MUA work on display here