As you correctly highlight, the problem she will have is the fact that she is already married. Legally there is not really any way that you can bring her here as a dependent of you while she is still married as even if you applied for a finance visa, you would have to be able to demonstrate that you were both free to marry in the 6 month period that would be granted. If you cannot do that, the visa application would most likely be refused. The unmarried partner visa is also not really an option for you since she is still legally married to someone else and you do not seem to have lived together in the UK for at least 2 years in a relationship akin to a marriage or outside the UK for 4 years on the same basis.
The other option for bringing her here is that she comes under the points based scheme as a worker but this is a complicated route to take and it involves her finding a job etc before she can come.
Legally there is little that you can do. If she is in danger in her country then she could seek protection from the authorities in India and if they fail to protect her, there is the option of seeking asylum in the UK but this is not something that you can do, she will have to do it herself and it is not a decision to be taXXXXX XXXXXghtly as the requirements for qualifying as an asylum seeker are strict and if her application fails then it can have adverse consequences for future applications she may make to come to the UK to live.
The best advice I can offer is to try and help her get out of the marriage from within India and then you can bring her here as your fiance or wife under the immigration rules.
I hope this answers your question in which case please accept. If you require any further information, please ask.
Are there no womens refuge's in India that she could seek assistance from in getting a divorce? In the UK there are organisations that assist women in getting out of violent situations and helping them seek legal advice to get a divorce, even if the spouse doesn't necessarily consent to it, particularly where violence is involved. Can you not go to India to assist her in this and then bring her to the UK as a fiance or spouse?