I had the exact same problems when i had my cossie. The first week of ownership and it blew a coolant hose, had to be towed home by the AA. Fixed that and then it decided to over boost.
It was really disheartening but don't let it get you down. All problems can be fixed, so keep at it.
I took my car for its first decent drive last week after solving a seiries of problems and i had an awsome laugh in it. So don't let it get you down.
By the way this board is awsome for advice, the amount of help i've had is brilliant, eveyones really helpful. Especially PJay, he's a gooden