I'm no expert as in a similar situation myself, but think about where you are advertising and perhaps do some research of other local girls to you and see where they advertise.
There is a very helpful thread on here about places to advertise and if you go through the whole of it it is region specific, so just get a pen and paper and note down where might apply to you. If you want to go really in depth, perhaps look and see if the same girls feature on a few sites, which would be a good indication those sites are working for them.
Also, ensure your photos are changed regularly, feature private galleries, which pays for your expenses on aw and keeps people checking you out.
I think it's the photos and ads that are the real issues - don't give a cut to an agency who won't check out clients, that's just silly. It's your body, that's just like paying a pimp when you are capable of sorting it all out yourself, you just need to think about where you can improve. Trial and error and not immediate, but you will work it out.
Loads of ladies on here know tonnes more than me, but in my limited experience that's a good start. Hope it helps. x