That's looking great. The river looks very cool, and I can see the texture in there.

The forest texture could to with being a little more subdued - it's very large for the map right now.

As for the buildings, you probably want to do the following. Create a selection of all of the buildings. Now create a new layer. Go to the gradient tool. Make sure your colours are black and white and change the Shape to Shaped(angular). Now click and drag (it doesn't matter how much) within one of the selected areas. This should give you nice sharp gradients from white to black on all of the buildings. You want the peaks to be white and the lower areas to be black. If this hasn't worked, switch the colours and do it again. Now create a new layer and fill it with 50% grey. Now Go to Filters->Map->Bump Map. In this window you need to select layer with the gradient filled buildings in the top right drop down menu. Now fiddle with the different settings until the preview window shows you an image you like. Note that you can specify the angle of the lighting here.

Once your bump mapping has been done, switch this grey layer's mode to overlay and you should have some nice shaped roofs. Sorry for the slightly rushed walkthrough, the mosaic town tutorial in my sig has a slightly longer description of this process in one of the later steps. Shout if you get stuck doing it, and I'll put together a slightly more structured tute.