I had water leaking into the car as well, and found that the heater hose was causing it. Hot water from the cooling system comes in through a hose in the firewall to heat your air in the dash, then goes back out through another hose back to the motor. As my car is old, and I live in the tropics and don't use the heater, I just cut the two hoses on the engine side of the firewall, and joined them together to recreate the loop, bypassing the heater in the dash. No more water in the car or musty smell either.
Hey, my 95 Barina Swing has had no problems. It has done over 250,000 klm, but just lately the auto is starting to play up, but that's the first thing to go wrong, so in will go another auto, no worries. I will keep her. Good on you Holden.
I think and believe you are gonna have problems with it for the rest of the car's life. My mate's daughter bought one of these, and spent almost twice what the car was worth. In the end she just took it in and traded it in on something better. I suggest you do the same thing, or sell it. It's better off in the long run. It's up to you what you wanna do with it, but I believe that would be an excellent option.
My 1996 Holden Barina, as soon as I start it, it just revs hard and I have to turn it off.