fix my head gasket for holden vectra?

Hello I just buy new car I save up for and I notice problems with head gasket., it is blowing lots of excessive smoke from the exhaust and when stationary there is a jittering feeling through the car. I do not want to have to buy another 2.2L motor for it, but I feel like I might need to.has any one else experienced this problem with these European four cylinder motors?. if I get any feedback about this motor, I will greatly appreciate it..Thank you.