Hi Dipak,
All the suggestions what you got above are very good suggestions. But before taking any decision please make sure the following points. I am writing this because of my experience and also some of the cases what happened in real.
1, Why your wife don't want to stay in joint family. Finding out this reason is very important. If you ask your wife in pleasing manner she may tell but chances are very less. You only have to find out by thinking as a gentle man and the events happened since your marriage. Think alone and try to come up why your wife may not be liking to stay in joint family. This is the first important step to take.
2. In one case happened wife did not liked to stay in joint family is that she had affair before marriage and the boy friend was still in touch even after marriage and for this reason she avoided joint family living. Unfortunately that girl even poisned his mother and she died. Then she left home and filed 498A. Bad part here is the boys side came to know that this happened only when she filed 498A. They initially thought naturally his mother died.
3. In one case the girl has color blindness and some diseases and she is afraid that parents may catch that and tried to avoid to allow his parents to stay.
4. In one case she will not have kids and so avoided to stay in joint family.
5. In some cases they are some how mindset is like that in laws will trouble so avoid them, this you have to solve temporarily moving to new house and educate her.
6. In some cases really in laws will trouble her or some times to adjust the life style of her home and this new home may not be suitable so that in good manner you have to tackle it.