Once the major issues are addressed ,its just routine maintenance that needs to be every couple of years.
These cars are really cheap to maintain.
If you car was a toyota/mitsubishi/honda you would have spent twice the amount of money.Then zen is a good car, I would suggest you keep it.
I would suggest getting all the critical work done ASAP
and rest spread them out in groups.
For example.If you have to have your brakes serviced and the suspension is giving you problems too.Do both jobs together.The wheels need to come off for both of them.This will save you labor and also alignment costs.
If you have to change the fluids in your car.Change them all out at once.
Try to get all the work done in groups.
This way the garage can't over charge you for labor.
Once you know what jobs you need to get done, call a few service centers and ask for a quote.Ask them to bifurcate the parts and labor costs and make sure you ask them to sign it once you agree that the total expenditure shouldn't go above the said estimate.
For cost of the recent repair, you have to admit you didn't read the signs and you just drove your car to the ground.The car gives you a lot of hints when its not working properly.A good driver needs to understand how his/her car behaves.This is the basic.You treat your car right, it will go on and on.