Lighten up the brown, and I think you have a winner. You can probably tint it a little more toward green, for color variety, but the idea is working much better with those textures.
Also, try getting the whole scene painted, in very low detail, first. If you are using PaintShopPro, or Photoshop pro, paste everything together, either on seperate layers, or make an individual layer, but make an ass ton of alpha channels, so you can reselect the exact pixels for each tile. I vote the later, because then you can have a single layer with all the numbered tiles to reffer to, which you can turn off and on as you need to. This will help you iron out all of the big problems before spending hours painting a few tiles, and finding out that tiling didn't work well, or an entire wall looks extremely bad when it is color X. Redoing details sucks, hard.
Relooking at the two colors you have, I actuallylike the color variety on the green. I still say brown, so it stays similar to the original scene, but try brightening up the lighter tone. Take some of the overall color from it as well. This will subdue the walls a little, and help the rest of the environment standout more, giving it a more 3D apearance.
Sorry for rambling. You're doing great! I wouldn't even have the patience to piece the damned thing together, forget cutting it back up to see whether or not tiling is effective. >_<