Also, if you can, convert it to a jpeg or something with a smaller file size.
As far as textures, (can’t see yours), if you can’t find an image on the net, etc., that you like, make your own with Gimp or Photoshop. Then either apply it as a regular texture or use the UV mapper in Blender.
A good begining. There are tons of free textures on the net, not that all of them are very good, but there are a few good sites. Why’s it in BMP format? You do know you can render images in jpg right? About the textures. I’m not sure how far you are, but if you go to the materials window you’ll see four buttons about in the middle. They say “Flat”,“Cube”,“Tube”, and “Sphere”. Hit the cube button and the textures should look a bit better. Keep adding detail to the model and good luck.