Tropical hibiscus plants frequently drop quite a few leaves when brought into the house in the fall. It's their way of adapting to new light levels inside. But they do usually put out new leaves fairly quickly. Perhaps the window is too cold for it? If so, it may have fallen into dormancy.

I have several tropical hibiscuses and keep the shorter ones under grow-lights during the winter, where they get about 16 hours of light per day. The largest, however, is in a big front window and does quite well there too. It has some smaller houseplants between it and the glass, which may help keep it from getting chilled! I've found the tropical hibiscuses to be quite tough plants, and they often produce a few blooms during the winter.

If you have any kind of light that stays on for most of the day, you might want to try setting the plant under it to see if that provokes a change. If not, you might just want to keep your hibiscus dormant all winter and try to get it going again in the spring. (In that case it would probably be best to put it in a cool, dim spot and water it only sparingly.)

Thank you Audrey.
You made me feel alot better.
I am going to put a shop light over it also to reinforce the light. It isn't getting enough light I guess due to our short days now.
This plant is extremely difficult to grow for some reason, but when it blooms in the summer it is so gorgeous!
Thanks again for your reply.