I Would Like to Buy a New Car

I just found my engine in my Toyota Corolla 95 and the failure of the procedure and the result placed in a hole through the engine block of my country. It will cost about 2800 dollars for the engine used and to be placed in my car. Now I know has been an old car, but in most of the highly reliable. And my mother only the previous owner of the car before me if you do not know the history of my car. I am a college student with not a lot of money, I would like to buy used 1996 Audi A6 for about 3500 U.S. dollars, which requires passenger window fixed, and the right auto repair mount which will raise the cost to about 4000 dollars. I know I am pretty much at a loss in all cases, but I just were not sure what I should lose. I am with someone else is using the car that you may pay more money than it should and must take a ton of fixes in it, but I am not sure if I put $ 2800 in a piece of my old but reliable unwanted is the best thing either . What should I do?