Do you have a website?...Perhaps you could get other websites to mention you and your show in a blog and link to your site.
Getting out and about at some horror conventions would be good.
Contests (people like winning stuff....maybe you could have people hang up flyers/postcards of Dr. Rotz's Laboratory and take a photo and send it to you...then you could have winners for stuff like the most creative place, the most flyers hung, the place where the flyer would get the most exposure....You could give away a prop used in one of your episodes, or a signed poster from you and Nurse Candy).
There might be something on fiverr.com
that could help you market (it's only 5 bucks to have someone mention you on their blog, radio show, etc).