I am so glad I found this post and I hope that I can be of help. You say that you do not have any money to work with for marketing, which certainly limits your options, but does not cripple you competitevly as much as you would think.
The first thing I would do is hire a consultant (me maybe
) to help strategize your business plan for the future. The absolute first thing you need to do is have a professional budget created to really help solidify your current earnings. The worst thing that you could do right now is be hemorrhaging money and not even know it.
The second thing you need to do is interact like crazy on AH.com. I really cannot think of a better marketing tool for African hunters than this website. You throw up a promotion or two and you are sure to get attention.
The third thing you need to do is update your website. Out of all of the african safari websites that I have looked at, I think that the African Sky Hunting website is by far the most accessible and appealing. Try to look at not only the content on their webpage, but also the visuals and layout. All of these are very important ot successful web marketing. It was also mentioned that Craig Boddington hunted with you. This is all you should talk about (clearly hyperbole but you know what I mean). Get his pictures and try to get a testimony from him all over your page.
The fifth thing you need to do is four walls marketing. If you do not know what this is, there are many good online resources to help. You say that a lot of your hunts are from agents of PHs who are overbooked etc. This is the perfect opportunity for you to convince them that the next time they hunt africa, it will be with you. This means brand recognition. You would be shocked to see what just a hat with a logo can do (just ask Jerome).
I hope this little bit was helpful. It was just a taste of all of the different strategies that you have available. If you want to talk more, please pm me. I am glad to be of help to any fellow hunter. This is the most advice I have ever given away for free. FYI, I will trade formal help for a free hunt
(just kidding...maybe).