You can buy some humane traps at depot stores, although you can make an equally affective trap at home with some supervision. Take a box and mount it up on a stick with a fork, and put a piece of food (Cheese?) and tie a string on the stick. Wait for the mouse to come and pull the string to capture it.
Use some glue traps. These work really well. You can get them at Walmart or other similar stores. I have a mouse get in once or twice and they catch them overnight. Place a couple around the baseboards. Mice don't see well and run along the edges of a room. They smell like peanut butter which mice love!
When I was livening in a basement apartment we use to get them all the time until I went to Walmart and picked up some Electronic mouse repellent. It works amazing you just plug it into to wall and it uses high-frequency sounds to keep things like mice,cockroaches and other creepy things away :p