First, change ad-hoc to adhoc (makes it one word).
When I did this business years ago, I had success with a classified in our local once a week paper, so go for it! Our town's newspaper is way too expensive for classifieds and when I ran one in the beginning, I got calls from people looking for work, so be prepared for that.
How about using:
Lia Neal offers exceptional admin services including word processing, transcription, presentations, data services and desktop publishing Call +######### www.website_address/
That tells exactly what you do, includes your domain name, phone number and has about 20 words.