problems with 2003 saab 9-3 linear
 

A few moths ago my husband and I purchased our 2003 Saab 9-3 linear off a dealer on craigslist. We thought we were getting a deal he told us about it needing a sway bar and needing to be balanced, and anti lock brake sensor needed to be replaced so we said that was fine we would still take it cause to be honest I thought it was such a nice car I was excited. Anyway before we bought it we took it to the saab dealership and paid them 85 to look at the car to let us know what was wrong with it, they said the same thing as the dealer we were buying it from. So we bought it and got the balancing done, the car still shook when I drove past 60 so it wasn't the balancing after all. I took it back to the dealer we bought it from and he says its not the sway bar its the suspension. So I felt like he wasn't being honest and took it to a mecahnic by the house he gave me a list of stuff that needed to be fixed icluding shocks and struts, oil pan, water pump and timing, and alot more. We ended up paying $2000 to get all that fixed. I went to pick it up about 2 weeks later cause apparently the parts take forever to come in and the shaking past 60 stopped, but when I turn I still hear this kind of knock noise, like something is loose or something or moves when I turn and turn it back straight. And the light keeps going on that says low coolent level so I also had to replace two heater hoses at 78 a piece. And the anti lock brake sensor light went on again. So I took it back he replaced it. And today I was driving and once again the low coolant light went on. I am so frustrated because we have put so much money into this car and its always in the shop. So if anyone has any idea what would cause this can you please offer some advice, also I forgot to mention after he fixed it another light came on it says stability control failure idk if that has to do with that noise I hear when I turn or what it could be if anyone know please help.