ISO: Hibiscus Plant

I had my Hibiscus plant on my balcony all summer, it thrived but now because nights are cooler I have taken it inside for the winter.....It is standing in front of a S/W exposure window where it gets light and sun...but leaves are getting yellow and falling off now even tho it is still flowering , not as much as outside but still flowering and I keep it watered nicely. However leaves are yellowing and falling off and at least two branches are empty of leaves but see little ones coming, will they come and what will I have to do to keep it flowering thru the winter months. It is very tall now about 3 ft. Should I cut it back and how much and will it survive thru the winter as I have been told it will? Really appreciate some help if possible, I don't want to lose it. Thank you so much....Maggie