It really needs dry roots -- too much water will rot them. You should have it potted so that it has good drainage. You usually bring a Rosemary indoors when the temp. starts dipping below 30F -- so if it doesn't get too much colder than that at night it should be fine outside. You can get a timed watering tube for pretty cheap. You just fill it with water and then stick it in the soil -- it will let water out a little at a time.

If I had to go with one or the other, I would put the plant outside -- overwatering it is bound to rot it before being too dry kills it.