Hi,
If you had made it clear in the documentation and source of the website that your software is GPL, then you can take legal measures. It is not clear to me how well GPL will hold in India, but those software were written by you and so you hold the copyright. Since you hold the copyright and you released the software under a specific license, that license _must_ be observed by the licensee.
What I cannot say is whether GPL holds under Indian Laws. I think it may, but then I am not a lawyer, so take my opinions on law with a pinch of salt.
However, there is more you can do than just legal action.
1. Threaten the guilty parties with a court case, explaining that you are not against their selling of your software (which GPL allows), but against their renaming etc. Also note that they cannot charge for the source code under GPL, but they may charge for executables, if they provide the source code too, or offer to do so for free. They may capitulate and agree to your demands. You can also threaten them that you will tell their customers and so on.
2. If that does not work, contact their Internet Service Provider (If they do business on internet) and tell them that they are selling your software Illegally. Typically the ISP will take your side and shut the website down. If it is an Indian ISP however, then I don't know what they will do. Shutting down the website will effectively cripple the business.
3. Contact press and try to get a press story. This will be easier in Local Newspapers.
4. Also try contacting the people in the Bangalore LUG. People there are quite experienced and may have more ideas.
Best regards,
Pallav