Hi, I don't know if they do one specifically for Goa, but try Footprints Guides. I'm going to Borneo at Easter and a friend bought me a copy of Footprints Borneo....he got it at W H Smiths I think......and it's excellent.
I dont think you can go wrong with Lonely Planet the India one has Goa not sure if they do a dedicated one for Goa but I been India 3 times including Goa and would have been lost without it at times