Best place to find a printed owners manual is ebay. But be prepared to spend up to $50 on a genuine factory manual for an old GPz1100. These are way better than Haynes / Clymer, if you intend to do more than just standard servicing jobs. A Clymer/Haynes manual is fine for doing all the simple things at home, and these are also a lot cheaper.
If your anti-dive is leaking, you need to replace a couple of o-rings inside the anti-dive mechanism which is bolted to each lower fork-leg. Its a pretty easy job......here is a picture of the lower fork leg. The part # you need is 92055-1201, and there are 4 required (2 for each fork leg)