For your rear dropouts, you can get a fully threaded aluminium shaft (3/8-5/16" x 5") at a good hardware store. Screw on a set of nuts and put the threaded shaft into your rear dropouts. Back the nuts out until they are contacting the inside of your dropouts. Then screw a second set of nuts on the outside of your dropouts. Tighten a little until you cannot move them. For your front dropouts, go to your local LBS and ask for the plastic dropout braces that come with all new bikes. Total cost should not exceed $4.00