Ross are good, but can be too busy to help.
Outback Automotive
Motor Engineers & Repairers - Alice Springs, NT
3484 Greatorex Rd, Alice Springs NT 0870
Phone
(08) 8952 0123
Andy is good, and very busy. He is handy with a welder too, so might be able to do both. 15 mins out of town in the rural area though.
Tim Wells operates out of his house in town, Ive found him very good also. 0408833741. I dont know if he has welding gear, he might be able to help.
http://www.countrydieselmaintenance.com.au/ many people say these guys are the best around, but it comes at a price. very thorough and professional.
Kiddles are known to be very expensive and charge for things that they don't do. Use them as a last resort. You might need to call around a bit, its a busy time of year.