Ok, we have an old Holden Apollo (1992, automatic) and since some days the battery light in the cockpit is lightning while driving sometimes, and sometimes not - the battery is also not charged very well it seems, as we needed a jumpstart today

And sorry about my english, it's my second language only, hope I made it understandable anyway.
Please if somebody could help us with a hint to avoid the high cost of a car repairer (my husband could change the generator by himself maybe, if it's the generator... he is just not as good with computers

Thanks in advance for your help, we appreciate everything that helps maybe (where do we get a cheap generator if it's the damaged part btw? we are at the sunshine coast)
Sunny