What I would say to do is bring the cat up on to your bed, then just keep peting the cat until they go to sleep, and once they go to sleep then you have your cat sleeping with you on your bed. But this might not work if you turn around alot in your sleep
There's not much you can do to force the issue - if your cat doesn't want to sleep in your bed, he/she isn't going to. You can encourage your cat to feel comfortable in your bed by gently placing him/her there and petting him/her in your bed. Over time, your cat may decide to sleep there.
Well the best way would just be to not let the cat in the house. When the cat comes inside you throw it out. Most cats wont just run inside. Don't let the cat sleep in your house either. You might want to provide your cat with a proper sleeping area with a bed or house of some form.