You have everything done but removing the sink. The water should be off and the supply lines disconnected from the valves. You probably don't need to remove the faucet as it will stay attached to the sink. Double check that all the sink hold-down screws are off. There are usually a minimum of 2 per side. Finally remove the connection between the drain tailpiece and the P-trap. If the sink is equipped with a disposer that needs to be removed. Post back if you need help. The sink should now be ready to remove.
If your sink is porcelein (cast iron) it will be too heavy to lift alone. Wait for your friend to help if that is the case. The rim of the sink may be set in a bead of plumbers putty. Try pushing the sink up from the bottom from inside the cabinet. If it doesn't budge, check for more hold down screws and try again.