well its not really a kit, just a belt. but most people change the water pump and the idler and tensioner bearings at the same time as they are meant to wear out soon after the timing belt is due. hence why it can usually cost a bit to change.
its easy to do though, only real tool ya need that isn't normal is the harmonic balancer puller, and they are like $20.
as for places to get it done, Hills Motor Sport, located in Castle hill, have been good for me so far. had a fare bit of work done through them in the past, rear end rebuild totally.
#02 9899 9962
the guy who runs the place's name is Mark.
as for parts, Just Jap are a good place to pick up the parts, good price. bit of a distance if you don't live south of sydney, but they will deliver pretty cheap.
#02 9545 0532
another good parts place is LinCorp. has all genuine nissan parts.
#02 8844 4400
another place, also good for parts but can also do the work i do belive, is Stuart Wilkins Motor Sport. they are out windsor way.
#02 4577 2400
if you're confident about doing this your self, do it. it'll save you alot in labour cost.
i would offer to do it for you, but im unsure when i'd have time to though.