I'm insulted you don't think 18MPG is good mileage
MY Dmax gets anywhere from 17-19 MPG unless its in REGEN then it falls to about 12MPG for 30 mins or so. Jenns challenger gets around 26MPG....not bad for a monster sized car. I hate buying used simply due to the fact YOU DONT KNOW what, where, or how the car got those 25k miles. Mighta been a nice easy driven car in a garage or it mighta been abused from 1 mile. Of course buying used usually saves you from eating the new car price, and you can definitely run into great deals.....but you can also end up in your shoes too.
Doesn't VW have warranty? If it were American made ( :D ) it would have 36K bumper to bumper and should be covered. I am pretty sure VW has the same doesn't it?
I would wager that you have a bad alternator as well. Seeing as how it set for a year, I'm not surprised it would be out.
I hope it's something simple and CHEAP!