Ahhh...ouch!!!!!!
Yep, I think you've definitely fried the ECU then...Mine happened when some low life tried to break into the car and shorted the battery out against the ECU body under the bonnet when they stuck something under to get to the bonnet catch/release...
The ECU was just over $1,000, labor and re-programmed to the keys etc should have been just over $250, however it was free as they owed me a favor from stuffing up a service years ago and they are trying to get my business back...
The only options you realistically have if the ECU is toast is to tow it to Holden, pay the $$$$'s and get them to fit and program a new ECU to the car...
Unless you can get a new ECU, security module, keys etc from somewhere and fit them yourself or get a trusted mechanic to do it...But they are almost impossible to find and getting it to work properly if you don;t do something right could end up an expensive waste of time, but you could try the Astra specialist wrecker in Sydney....