A new set of replacement fins is pricey...
I think in the past, Stafford at Adventurekiteboarding.com has had some replacement fins for the V2 Sector available.
Another option I have seen (on a V1 board at least) is to move your trailing fins up to the lead spot and then use a mini-tuttle to FCS Adapter as shown below to put on some FCS trailing fins:http://www.surfstationstore.com/nsp-fcs-adapter/dp/21830
This reportedly gives the board a more surfy feel at the expense of some Lightwind/Upwind performance.
The V2 outline tail outline is a little wider, and I don't know for sure how it would ride with the smaller fins, but it is a possibility.