Not starting/engine

I've been having a few problems with my truck. My heater hose keeps breaking at the connector. I got that fixed and it keeps breaking. Now my truck is not starting before it went out it was a lot of white smoke coming out of my tailpipe as well as the back of my engine and I'm smelling gas I went to AutoZone to get a code read and it stated that I have a fuel injector problem and a intake manifold gasket problem. The car cranks but it doesn't start now my engine light was previously blinking also. My temp gauge is not working sometimes it works and most of the time it doesn't. It overheats sometimes also. There was brown liquid stuff on the outside of my oil cap in the front of my engine when it went out and there is oily all on the back of the engine hoses. There is coolant coming out of the side of the engine also. Please someone help me and tell me if it could be saved or should I just toss it. Please give an estimate of price it will cost to fix please help. Thanks