If you only need it for a year, and your budget is $5-7K, you should suck it up and buy a used Civic or Focus. Some European cars are still young at 130K+ miles, but not typically an entry model like the A4, or a BMW318, and definitely not Mercedes. You will loose your wallet and your pants with it if anything breaks.
I agree with what has been said about the Audi V6 engine, and also about the maintenance. The 4 cyl is more robust, but still not without issue. I bought a 1997 A4 1.8 Quattro new. Drove it for 18 months, then bailed out on it just before the included scheduled maintenance ran out at 50K miles. I prefer to keep cars for the long haul, but my experiences with Audi during those first 50,000 miles were sufficient to cause me to buy another car. Fortunately, it was worth more than I owed on it. The wastegate control rod broke off at the brazing in less than 10K miles, leaving me with a car that had the acceleration of a Yugo. They fixed it though. Had to do the brakes at 36,000 miles. I had numerous problems with the stereo head unit. Getrag makes a great gearbox, but I had troubles with mine. Awesome traction, but at what cost?
I replaced the car with a Saab 93SE in 1999, and drove that car for five years and about 145K miles. Did the rear brakes at about 90,000 miles, did the clutch at around 120K miles, and that's about it. Drove it like I stole it. Never replaced the battery, no tranny issues, excellent brakes. The car held alignment the entire time, tracking as true as can be. So it ended up actually being an inexpensive car to have owned, at the end of about 5 years. Undue maintenance in a euro car can ruin your day in a moment.
