I agree with Tom.
I would also invest heavily in customer service training. Allocate a budget toward customer refunds if you haven’t already, and be liberal with your policies in making customers happy. That will ensure repeat business & referrals – which are the quickest way to grow. Have a good way to manage your online reputation as well. A service business can live & die based on their reputation.
A strong focus on other digital marketing efforts would be good: pay-per-click, SEO, and email marketing. If you can afford it, start a regular direct mail campaign to targeted areas within a 7 mile radius of your shop.
I don’t particularly recommend investing with Yelp. If you can manage to score a great reputation on Yelp, you’ll never need to spend a dime advertising with them (although you might choose to test it out in the future).