4) You will need to have on hand water line repair tape, small gas torch, solder, flux, plumbing sandpaper, pipe cutter, gas tape (to seal gas line) and maybe some pipe glue. Ask the sales person at the hardware store for a more defined list.
There are two, one on each side of the toilet, closet bolts which hold the toilet to the floor. If there are caps over the bolts, remove or pop them open. Using a small crescent wrench unscrew the nuts from the bolts. Alternate side to side when unscrewing this will be much more important when reinstalling the water line repair bolts but alternate anyhow.
Offers 24-hour service. They are called emergency plumbers for a reason. If your pipe broke in the middle of the night, you can't just turn off your water source until the next morning when a plumber is available. Search the internet for plumbing that offers 24-hour services in your area, or look them up at the directory listing. Surely one or two companies exist in your community.
Once you have disconnected the tank remove it from your work space. Do a thorough measurement of the remaining pipe for reference when you go to the hardware store. I will be honest with you, you might need to make a few trips back to the store. Once you get the new tank, slide it into place to line up the plumbing.
The first step in the replacement project is to turn off the water line repair to the toilet and flush any water that may be in the tank. If you forget this step, you will have a giant mess to clean up! You should now disconnect that water line.
Turn the water off at the main shutoff valve at the street. You should be able to take a pair of pliers(or your bare hands) and turn the valve at the water meter to shut off the water to your home. Once you have shut off the water you can cut the pipe around the leak and make the repair.
Find out if the plumber works on a 24 hour basis and, if so, what are the extra charges involved. More important than the costs however are the person's trustworthiness and reputation. After all, he or she will be in your home and around your possessions. You should feel comfortable with their presence and confident that they are honest.