Donnie is right, this is not exactly DIY! You can do it if you are determined.... I put one in my 300D. Took forever, and a lot of cussing, but I DID IT!
For now, you can nudge the window closed. Open the door, stand with one hand on each side of the door, and place your hands together with the window between your palms. Gently lift the window closed. It will slowly move up, just be careful not to force it too much. If the regulator is what is shot, this will not damage anything that is not already gone. It also helps if someone can push the UP button while you lift.