GOOD BLOODY GOD!!! It's a God damned mouse, not a cobra! Here's some choices for you. Some are obviously more effective than others.
1) Mouse trap...take bets as to whether the head gets completely severed or not.
2) Shotgun. Don't use a rifle since the bullet could go right though your wall, into your neighbor's bedroom, and kill him too.
3) Cat. Duh.
4) Get a bunch of those green blocks of rat poison from any store. Throw them around everywhere. Within a few days, the mouse problem is guaranteed to be gone. **WARNING** If you don't like the smell of rotting flesh that you may or may not be able to find, you might want to leave the house for a few days. Don't worry, it goes away in time.