A little vinegar in the water in the spray bottle.
A can of compressed air.
A mouse trap upside down so when it goes off it won't actually catch kitty but will scare the little one.
A piece hot dog with thread tied to it. Tie the other end of the thread to a couple of coke cans so when kitty jumps up and steals hotdog the cans chase it away.
Hot sauce or Tabasco sauce.
Vicks Vapo-rub.