Does the earth go further away from the sun in the winter?
Yes. The earth, and all the planets, are not on perfectly circular orbits, but rather elliptical orbits. During the winter months (depending on hemisphere), the earth happens to be at one of the far ends of the elliptical path. This is why it is summer in Australia when it is winter in Alaska (which is practically winter all year anyways…cold up here). Likewise, when the earth’s path is closer to the sun, it is warmer (spring). Summer actually occurs when the earth is at a “far end”, but it is tilted towards the sun, thus receiving direct rays from the sun. As it travels around, the rays are less direct, and it becomes fall (closest to the sun, but tilted away), and then winter (far away and tilted away), and then spring (close and partially tilted towards sun).
