Know-How Exchange : Advertising/PR

We have been in business for 1 year. We only have 41 members to show for it. We have spent over $30k on ads (Valpak, money mailer, flyers in local paper in the surrounding zip codes) and we get very little response, between 0 to 9 total calls in a month on 20,000 to 40,000 mailings/flyers. We did do well on one flyer in the paper for our Grand Opening (4 months after we were officially open), we had 30 people in one day and 20 signed up. We are similar to Curves for Women, but better in the respect that we have extremely better hours thru the use of a proximity card entrance when staff is not on duty, so we are open 365 days and are hours are 5am to 10:30pm. Also, we have special classes done by instructors ie. Strength training, Abs class, Pilates, that Curves does not have. And, we have better equipment, were members can adjust the tension on the equipment, with Curves you can not do this. We have expressed this in our advertisements. We are in a city of aprox 500k and we have aprox 65k people in a 3-mile radius of our gym. Of our members only 25 actually signed up thru our advertising (20 in one day), the rest just saw our business while getting a video at blockbusters in our strip mall. We are in a visible location, yet some of the people that have recently become members said they passed by us every day for a year and never noticed us. I just do not know what we are doing wrong. Any help would be appreciated. We have about 3 months left to get membership up or we will not make it. We have about $15k left for advertising. Any Ideas?