Well as graphics are the order of the day, you have my GP suggestions, here are some for graphics to try and get the next version looking more as it should.
Tiled wall - the tiles are to big, make the 25-50 smaller. This will give the poster a sense of size.
Paper background - bin this completely, you will never get this to work. It needs to be crisp with a sense of cleanliness.
Give the poster a nice frame - something in wood or metal but it needs to be clean and crisp.
Title - move to the middle (where the flies are) and give it a better font. Try this one. http://www.dafont.com/american-dream.font?fpp=50
Remove version 11 and what not. Not needed at all on the map.
Bonuses - make into a chalk board with prices. This will really help.
Sig - move to the bottom right of the poster itself and onto the tiles.
Little pieces of paper - when have you ever seen this in a butchers shop. All need to go and any relevant info goes onto the chalk board.
Bonus regions - have a look at splitting these apart. You have the room. Then you can put a meat texture over the whole thing or even a split up photo of a real cow. And lose the awful colours.
Army circles, unless you really need them, lose them.
Thats enough for now.
Game play side of things incase you missed them.
Bring in the other two legs like you did for the island map.
Lose flies, cow pat, grass.
Replace the grass with some scales and a normal 2 neutral attacked the same way as it is now.
Make the last two auto deploys normal bonuses with the 3 neutral on.
Remove all attack routes like tongue to grass.
Your fat barriers look OK but not too sure on the bonus numbers but they do look way off.
I know it is a lot to get your head around but it might be better to start from scratch as right now, the only thing that might be worth keeping is the cow itself.
These are bog standard images from the web but should give you an idea of how to make the poster itself look.
or you can go artistic if you feel adventurous.