I come from a nuclear family. There are only two people in my family; (my) husband and me. Although my extended family is quite large, there are (only) six people in my immediate family; my parents, my younger brother, my husband and my uncle. I added 'my' before 'husband' and changed 'just' to 'only' because it sounds better to my ear. But I completely understand what you mean. Nice job!

I would quibble with the word "come" when you talk about a nuclear family. It would be better "live in" am "part of" as getting married is more of a choice. But, for a good mark in IELTS you should look to expand. Tell the examiner a bit about your family.