I'll echo what Jay said, throwing a tree that has been inside a warm store, out to the weather now might put it to death.
Find a sunny window in a cool area, mist the foliage often, and be sure to check the soil to keep it moist not wet, and water the tree when it needs it. The typical watering instructions are to dunk it for 5 -10 min., once a week and enjoy your new indoor bonsai. Resist that bad advise and read through a bunch of threads you will find with the forums search feature, about watering and care.
Go to the FAQ, and beginners sections, lots of great info to get you thinking. Try this first
http://forum.bonsaitalk.com/showthread.php?t=17754 , good luck, and happy Bonsai-ing.
This should help you come up with about 50 more questions.
But next year no inside for this tree.
Bill