I-No from Guilty Gear you mean?
Well the hat is pretty straight-forward. Just get a witch hat from a halloween store, walmart, party city, or off ebay. They have ones in silk, cloth, and leather in a variety of colors.
And as for the guitar, I'd ask around if any friends have one they're willing to let you borrow. I personally wouldn't want to carry around that heavy (or that expensive) a prop. It's a risk that it'd get damaged or stolen. There's a tutorial by fellow cosplay.com user featherweight on how to construct a guitar from cardboard here:
Last suggestion is just to go to Toys R Us and buy a kiddy guitar. You can always add onto a kiddy guitar with poster board.