Car Troubles: What should I do and/or look for to fix my car?

Below is a list of the ongoing issues that I have endured with my 1999 Volkswagen Passat every since I purchased it from a used car dealership about a year ago:

1) About 5 months ago the A/C went without warning. One afternoon, as I was leaving a store, I noticed my A/C just wouldn't turn on --which includes the fan, blower, and defrost. The lights that are associated with the defrost and A/C, dashboard, and car lights work just fine though.

2) I may need rotors for my front tires (they make this really loud and annoying screeching noise whenever I press the brakes). I had the front brake pads replaced about a month or two ago.

3) Whenever the car is put in reverse or drive, and even when it fully stops after braking, it makes a clinking sound. What is that sound and does it have anything to do with the transmission?

4) Someones after gas is put in the car, it stalls at the gas station.

5) Rear driver side window of my car has somehow slipped off of the track. I took the car to a nearby Grease Monkey and the mechanic told me I may need a new motor for the window.

6) The blinker switch (the switch the controls the turning signals) is really loose. And the box that shields the wires under and around the steering wheel is separating.

7) The car has an alignment issue as well (It veers off to the right periodically, even when my hands are on the wheel. It is sometimes hard to control the wheel).

8) Lastly, since the car's A/C and heat is not working, the car shakes violently in the morning, and sometimes while driving and braking; especially since temperatures have reached below 25 degrees at night where I live.

At this point, I am not really sure what to do with the car. I really want to keep it --mainly because it is my first car. When I first bought it in January of 2013, it did not show any signs of malfunctioning to this extent. The only minor problems I had was with the brakes, which started around February of 2013, and the radio, which I had replaced shortly after I purchased the car. Maybe it is an electrical problem? I'm not really sure where I can find anything to fix this stuff for cheap.

What I really need to know is whether I should purchase parts for the car to fix these problems; should I take the car to a Volkswagen dealership for a broader understanding of these issues? Or is the car a total lose and should I sell it for what it is worth based on its current condition and Blue Book value? I really need an answer to every questions. It would really help!