HELP! I have a poor orphan baby painted turtle!?

Ok so today i was walking around my backyard. . .and i saw my cat playing with somthing no bigger than the top of a soda can, so i went over to see what it was , and it was a baby painted turtle! At first all i could think was how cute! but then i realized that i couldnt just leave it there! My cat would eat it! so i took it in my house and ive been on the computer for hours and i cant seem to find any answers so i came here!. . . So um if you can. . .can you please explain to my the nature of painted turtles? and a temporary way for my to care for my lil buddy!