I want to add few lines here and it may help you to organize your work flow or make the current better.
I agree with you that buying a list with potential client will be waist of money and time for you.
Hiring an employees/sales people will be a challenging because everybody need to fed a family.
As I have read some of your answer I see that your are in position of luck of clients and lack of sales. I have been there....
The way we got out is by creating more opportunities, leads and give flexibility to your employees/sales people, let them work part time, offer 1/3 of a salary for 3 month of probation....this way you will have 3 people working on cost of one and you will find a good staff and hire them.
You just focus on generating leads.