Alternator/generator/regulator problems of the 2002 Dodge Intrepid

We bought a 2002 used in 2005. It ran okay, thoughe h the oil pressure light and engine light would come on when idling. We were assured by the dealer we bought it from that it was just sensor and not to worry. Had some small problems with it, nothing too major. They just seemed to happen all the time. Then in 3/09 the alternator and water pump went out for the 2nd time, and even after repair the car would over heat out of no where and without warning. Continued to have the problems with the oil pressure light and engine light. Should have gotten rid of it then, but didn't have the money for a new car. Then in 11/09 the car did the overheat for no reason while my husband was going 70 mph on the highway, thank god there wasn't an accident. The gauges didn't indicate anything, all of them including the spedometer went to 0. It started gushing water and antifreeze. The engine is shot, it is now a gold lawn ornament. We maintained the car, oil changes every 3000mi etc. Was told its due to "sludge" in the engine and that its a common problem with Dodges 2. 7 engines. Wish I would've known this before I bought the car, and I wish someone would do something about the ton yard ornament I now have.