If it is just the leading edge ( ie No bladder damage ) take it direct to a sail maker......
eg: Thompson Sails
03 9571 8677 ( Glenhuntly rd Caulfield )
From memory a full seam to seam leading to trailing edge of canopy cost me about $60 ( a few years ago )
Turn around was about 1 week. Just make sure your kite is free of sand, sailmakers hate unfolding kites to find half the beach fall out all over their loft floor.
You can take it to RPS or SHQ but all they do is send it to Goodall Sails or similar who charge considerably more and then the shops add a percentage as well.
If it is a bladder and canopy repair..... I would recommend you send it to Moti Levi
www.kiterepair.com.au/They have a good reputation and quick turn arounds, you just post them your kite and a week later they post it back.