Hi Chirag,
fetching of custom data along with standard data there is a 2 ways.
1).adding custom field to the standard structure and fetching data.
2) adding custom field to the standard structure and fetching data by using badi.
in your case first approach is not applicable then go for second approach first go through the below links..
this thread similar to your requirement what you have posted.
Enhance Product Search Criteria by a Custom field
Enhance default search criteria
if you want to find out a badi for product then go to this link..
How to find Badi or Enhancement spot from Web UI
Thanks & Regards,
Srinivas.