Check out the Microshift brand shifters which will work with your setup or you could even go to a 10 speed set which would require just a new 10 speed cassette while keeping the same derailleurs. A new 9 speed shifter set can be had for around $140US or less. I noticed AU Ebay has a few single right shifters for sale as well as sets. A few forum members use them and are very happy. Road Drop Bar Shifters | microSHIFT