The WindPro II is a really nice stove. I'm not aware of MSR selling a parts kit for it. The only parts kit I'm aware of is their "annual maintenance" kit for stoves, but that's really for white gas stoves.

The most essential pieces of gear for a gas stove are:
1. A spare "O" ring for where the canister screws into the valve.
2. A "pricker" which is a thin wire that can be used to clear the jet.

You'll probably never need either, but if you do get a jam in the jet, you'll be grateful for that pricker, and that "O" ring is what allows you to get a good seal at the canister connection.

HJ