If the cyst continues to grow you could have just the cyst removed which is called a cystectomy. Even though it encases the ovary, a surgeon with good cystectomy skills should be able to remove just the cyst allowing you to keep your ovary and its hormones that are essential to good health. Studies show that both ovaries as well as the uterus are important our whole lives for good health and well-being. These links are helpful -
http://www.overy.org/ (Ovaries for Life)
There should be no need for a hysterectomy. Fibroids are very common and usually don't need any sort of treatment. If you have heavy or irregular bleeding, that can be treated with medication. And if the fibroid is large and pressing on organs such as your bladder, there is a surgery to remove JUST the fibroid (myomectomy) thereby leaving your uterus and its many lifelong functions intact.
Most ovarian cysts resolve on their own. It can be hard to tell if a cyst is truly complex or multiple simple cysts. How large are the cysts? Ovaries are very small so "totally encasing the ovary" still may not be that large. Do you have a copy of the ultrasound report?