In small servings of 1 tablespoon or so, butter and cream have very little lactose and can probably be enjoyed without causing symptoms. Yogurt actually loses lactose while it sits in your fridge. Keeping it for a while before you eat it may reduce the chance that it could cause symptoms. Ask your pharmacist about lactase products that may help you enjoy dairy foods without causing symptoms In some Australian states, long-life low lactose milks are available in supermarkets. After your symptoms have stopped for a while, you may be able to increase your lactose without further problems.
Many people find that they become more tolerant of lactose with time.
With lactose intolerance there are limits to how much lactose you can have without causing symptoms. That usually means about 8-10 grams per day. Dairy foods should not be completely eliminated from your diet because they are rich in vitamins and minerals you need. Full cream milk will be easier for you to digest than low fat or skim milk. Most cheeses have almost no lactose, so you don't have to limit them.