I have been contracting administrative services to a small business and have been invoicing her every month. How do I enter these earnings into Turbotax?

Income from your contracting services is considered self-employment/business income for tax purposes. You'll enter it in the business/self-employed section of TurboTax along with other details such as the name and address of your business (can be your name and address if you don't have an "official" name) and any associated expenses you had to earn the income.