Indian Arms or India Arms?  The latter is an Indian (Hindi) firm that makes weapons on contract, primarily for Savage (or used to, anyway).  They also sold or sell guns made in countries other than India, such as the Walther, which are also stamped as India Arms, much like Interarms marks the European made pistols they sell. 

If this is correct, a standard Walther manual should do the trick.  You can download them as .pdf files from http://www.impactguns.com/store/walther_manuals.html

If it is not India Arms Co., can you send the exact working of the markings on the gun and I'll give another shot at trying to find something for you. 

There was an Indian Arms that went out of business back in the 70's or 80's that made an "almost" exact version of Walther PP or PPK (?); the Walther manuals would work best for it.  Someone, somewhen told me that there was an issue with magazines, but I can't recall what the deal was.  (As I'm older, so is my memory.)  Is this what you have?

Pic 2

Looks like a PPK so the Walther manual should work.

At the gun show the other day a friend of mine suggested the magazine from the Indian won't fit correctly in the Walther and vice versa.  If you need magazines you might try Numrich Gun Parts at http://www.e-gunparts.com/