Hi,
It is hard to tell how old it is, but my guess is 19th century, the inner blade is probably one hundred years or more older. Most types were made over a period of several hundred years, with only small variations, so a precise dating is very problematic. Even when a weapon has a year inlaid, this can not always be trusted, it can have been inlaid later, at the time the weapon was made – or it can even be a year fifty or a hundred years older than the weapon.
Notice also that some decorations can have been added later, so you may have two ‘types’ of decorations.
On the link you will find a katar with silver decoration a bit like yours. This is called a Garsoe katar and the characteristics for this type of katar is the way the side guards are formed – they are not straight
http://www.vikingsword.com/ubb/Forum1/HTML/001461.html these kind of katars come from Sind. You will find Sind in the western part of India, where the harbour town Karachi is.
Try to find old maps of India on Google; this will help you to locate the different places.
The katar shown is typically for south India.